Wow David,
You really are at ground zero.  I'm not even sure where to start.

Your project is really ambitious, not impossible, but people make a living modifying off road vehicles.  It all takes time, and a pile of cash.

Well, lets start with your welding.  Yeah there's lots of books and video's on YouTube but you really need someone to teach you.  Gas Metal Arc, Oxy-Fuel, Tungsten Arc...doesn't matter which weld process you choose, you'll need someone to give you some practical training.  You gotta get structural element right (design and fab).

My 2 cents

Tyrone