I ran 235x75-15 tires for years before
I did all the lift mods.
I used to buy BFG Trailmaker tires from
Pace Club, before it changed to Costco,
great tire, wears long time, but I don't
even know if that tire is still made.
You don't need gears, the 235 tire corrected
my speedometer to read 100% correct, I
thought it was funny, but stock tires read 2-3
MPH faster than true speed, (smaller tire= more
wheel RPM) which is interpreted by the speedo as
faster that real speed.
The stock wheels are fine with 235 tires, geez I
got 31x10.5s on my stock rims ...... LOL
Lockers are not hard, but you might want to
have it installed, unless ur a mechanical nut
like me

.
Let me tell you a locker makes a huge difference,
it's like a 25% increase in traction over open diffs.
Have fun
Darrin