hey guys how long of a wheelbase is a good crawling w/b? ive seen alot of guys right around 100" give or take a few. and also would it be better to move the front axle forward, or the rear axle backwards, or a little bit of both?
THANKS!!!
Robbie

The bigger the tire the longer the wheel base, you could fill your tires with water if your worried about going over.

fill them with water? what does that do?

Makes them really heavy. 

Wheelbase really depends on where you are at.  100-107 is just about perfect with 35-37 inch tires.  Long enough to climb walls but still short enough to be maneuverable.  But if you live in an area with lots of light trails you probably want to stay around stock, maybe stretch to 90 or so.

And as mrfuelish said, you extend the wheelbase you need larger tires to compensate for the decrease in your break over point.

As far as extending the front or rear, probably both would be best.  Keep your weight as close to 50/50 as possible.  Plus you can give yourself a better approach and departer angle. 

heavy so all 4 wheels stay on the ground?

is there any tips on ways to extend the frame or move the axles?

THANkS AGAIN
Robbie

If you did it yes, they would stay on the ground.  Your center of gravity would drop as your wheels would probably weigh more then your vehicle.  Have fun driving them though.  Not to mention all the water sloshing around. 

The easiest solution for extending the axles is either longer springs or relocating your spring pads on your axle.  If you want to really spread it out, your best bet is probably a coil over solution.

This is optimum because on the front your steering is the furthest item out, and on the rear it is simply your spring mounts.  Take a look at some Buggy designs to see how switching to a coil over solution will make spreading your wheel base a lot easier.

If you want to keep it simpler, the Missing Link setup from Trail Tough for running Jeep YJ springs is a solid way to extend the wheelbase a bit while not doing to many modifications.  Or you can do the Rear Spring Up Front/CJ Springs in Rear conversion.

how far can i move the axles up on the frame with coils so that its still strong enough to hold up? or am i gonna need to add some frame support to achieve 100 inches of w/b?

Unless you are planning on jumping it you probably won't need to add any frame reinforcement.

If your worried about it though, just tie your roll cage into the frame.  That should add the extra strength you need.