mod-individual-progression VS mod-autobalance

3.3.5 has a lot of modding tools developed for it and the most active modding community so it seems like the natural choice unless you really prefer vanilla over wrath and don't want to spend too much time reverting changes, though there's a module called individual progression that has already done a ton of the heavy lifting for you in this area.

ChromieCraft is a good option to casually explore solo content, most zones are not contested and as it is running on 3.3.5 soloing most vanilla content is possible. Currently in TBC phase. You will not be able to use those AddOns though, would require a new setup from your side. Otherwise you can also run your own AzerothCore server with some modules to get a singleplayer experience. Check this.

just play this, no need for bots with terrible ai. https://github.com/ZhengPeiRu21/mod-individual-progression/releases/tag/20234020

I was looking at experimenting with adding in occasional abilities to spice things up (early priest can be very dull) and further bend the rules, but it would appear skills (like dual wield or armor proficiencies) are locked to particular classes and cannot be added in by GM rules. I am running this package presently: https://github.com/ZhengPeiRu21/mod-individual-progression.

I suggest AzerothCore + https://github.com/ZhengPeiRu21/mod-individual-progression/releases so u can play from Vanilla till Wotlk . After that its pretty hard to find good cores

I dunno about how these bots work but from my experience they're almost always a pain to play with and I'd rather avoid them. Instead I recommend using the AutoBalance module to tune health and damage of enemies and bosses. I'm currently playing with this repack and it's pretty good. I set the level cap to 60 and am running vanilla endgame dungeons. It's a bit hacky and cheesy but great fun.

the other comment showed us the github from the creator, looks like alot of info is there, but this will answer your question https://github.com/ZhengPeiRu21/mod-individual-progression

I can recommend NPCBots, they are much more functional than playerbots right now. The difference is they work only as companions and don't do anything in open world on their own. mod-autobalance is also excellent alternative to solocraft. Instead of boosting player stats it scales down dungeons and raids to any player count.