Chris Avallone comes straight out and says that while they might exist it would be like finding a unicorn, the man with the mule does imply that they did make it through, but in probably severely diminished numbers. Probably even worse than most animals, and NV breaks lore a lot but the dead horses could of found them in picture books man. Zion is after all a preserve.
What's true in the Mojave Desert, an arid California, and Washington DC is most likely not as true in a state confirmed to have wild horses living in it, and with a somewhat-active horse-rancher industry to boot. Though I'm not sure how many wild horses live in Zhang's home of Atlanta, Georgia, it's totally justifiable for there to be horses (both wild and feral) in the post-war Carolinas.
Along with horses i think mules went; but Brahmin, or a giddy-up-buttercup works, which is a tiny robotic pony.
There is no canon mention of mules and donkeys being extinct. In Fallout, you can find a recently-dead mule. In Fallout 2, there is reference to mare's milk being in good supply. In Fallout New Vegas, the Dead Horses obviously know that horses exist. In real life, wild horses are still astonishingly common out west. A nuclear apocalypse would cause some upheaval in their numbers, but if dogs and cattle can survive, a horse could too. To think that every single species of equid in America is extinct is, quite frankly, silly.
Personally, the way I'd do it is to split the group into those whose characters are combat-aligned, and those whose characters aren't. Then, you give them separate objectives and locations they can head to. One, for the combat-aligned characters, will be heavy on the combat. The other will have a greater focus on non-combat skills, like a town in dire need of support or something.
It could be something like the fighting has already began and those with weapons at quick disposal are firing back as those who aren't have some time to get their weapons ready to join the fray.
What I mean is "what about the characters who aren't well-suited for combat?" Unless that kindly old scientist or that backpacker suddenly busts out ninja moves, they won't get much of a chance to shine in a combat-heavy RP, which a lot of "everyone's in a big group" RPs turn into.
Putting us all in one group could work, if the threats we're dealing with are, like, gigantic camps full of people. However, that would kinda result in the less combat-ready characters getting caught behind.
Shazay pursed his lips, trying to remember African history through the haze of barely-remembered college classes. He did take a contemporary world history class, but only to sell Loa Dust to the students. What was it that happened in Africa...?
"Far as I know, whitey won in Africa an' enslaved the spearchuckers. Then you had 'em mine gold and diamonds and shit. Then some big lawyer named Mandela went round and started apartheid or some shit. Now they've got equal rights and De Beers mines gold and diamonds."
Shazay opted not to tell Frederick about the rich history of civil rights in America. Though he'd probably like the parts with the fire hoses, Frederick might not enjoy the ending.
"Aight, since you think you ain't a greenhorn, why don't you lead the way? Any bugbears or gangbangers come this way, you blast 'em. I'm gonna take the salt, and the cat lady can take the back. Any luck, we're done 'fore Hi-Hat's done with the king."
Hi-Hat & Xiangshi, Castle Tepes Front Gate, Nox
Hi-Hat breathed a deep sigh, and turned to look at the castle's gates. It was imposing, sure, but Hi-Hat had been through worse. "Alright," he said, turning to look at Dr. Facilier. "Let's get out story straight: Shadow Eternity is on the way, and we know it. They probably don't. So, we're offering our help and a bit of intel. Now, without any further ado, let's get this shitshow started."
Hi-Hat reached up and took a mighty pull at the gate's massive doorknocker. As the knob swung back into the thick wood of the door, a mighty knocking sound reverberated through the castle.
Four years of education on pre-war history. Primary focus on the Byzantine Empire and late Germanic tribes.
Discipline
Literacy, both reading and writing
Skilled at rudimentary weapon manufacturing, maintenance, and usage (includes simple firearms)
Background: Born in one of the dozens of villages spread throughout Legion territory, Albus was raised from birth to be an auxiliary soldier of Caesar's Legion. As he grew up, he learned everything Caesar had made policy to be learned: skills necessary to live on one's own, skills necessary to aid your fellow soldiers, and skills necessary to not make the mistakes of the proud, fattened hogs of the West. The way things were going, Caesar's Legion was primed to eradicate the men of the West.
When, against all odds, the NCR won the battle of Hoover Dam, and successfully assassinated both Caesar and his most-trusted confidants, the internal structure of The Legion collapsed into several warring nation-states. Clusters of villages rallied under the charismatic force of those who used to be Centurions, and so a massive civil war erupted across the American Southwest that rendered much of the land nearly impossible to traverse for fear of being attacked. Those who had previously rid the land of Raiders now banded together into massive tribes, raiding and assaulting their enemies with little mercy.
Albus was one of the many smaller villages who fled for safer grounds when the great civil war erupted. Together with his instructor, his mother, and his three brothers, he fled northeast. Though his family and friends decided to settle down somewhere in what used to be Kentucky, Albus moved along on his own, eventually reaching South Carolina in one piece. Currently, Albus is staying temporarily in a podunk shantytown way off on the coast, darning socks and hunting Mirelurks with the local boys.
Equipment:
One slightly dinged-up .357 lever-action rifle, given to him by his father.
One canteen, currently filled with water.
One pouch, filled with emergency rations. Enough for two days.
One baggy of trail mix, for Heather.
Fifty .357 magnum rounds, loose, bought from local scrap dealer.
One machete. Has a smiley face carved into the pommel and a crude guard made of wrapped cloth.
One road map. Covers both the Carolinas and Georgia.
One boning knife, for fish and small animals.
One tin drinking cup. Has multiple coffee stains.
One crude tank-top and pants, self-made.
One rucksack, stolen off an unknown corpse.
One straight razor, well-kept.
One iron saucepan, for boiling and cooking.
One ladle, wooden. Previously owned by mother.
One sewing kit. Previously owned by father.
Fifty bottle caps. Branded "Bawlz Energy Drink".
One pair of binoculars. One lens has been destroyed.
Three Legion denarii. Two silver, one gold.
Pair of shoes. Intermittently houses a growing colony of foot fungus and several large insects.
Other: Albus has one pet: an old wild pig that he managed to coerce into following him through regular bribery of dried meat. The pig's name is Heather. Heather is astonishingly intelligent, and frustratingly willful. Heather will go nearly anywhere Albus will go, and has saved Albus's skin more than once. Albus holds contempt for people affiliated with the NCR or the current Brotherhood of Steel. He feels that they haven't faced any real hardships and are instead growing fat off the backs of the workers beneath them.
Question. What is the timeline we are going off of here? Did the Lone Wanderer poison the water supply or purify it? What of all the smaller choices you make in game? Is Megaton still there or did the Lone Wanderer blow it up? What of the Courier? Which side did he/she choose? What of the groups the Courier affected?
On the New Vegas side of canon, it appears the RP is running off the NCR ending, and the Mojave Brotherhood of Steel has been convinced to peaceably leave the West Coast and regroup with the outlier group (the ones who wanted to interact with Wastelanders instead of just taking any technology they can find) they sent out east circa Fallout Tactics.