You cant do that the body is rubber mounted to the chassis.so will also be fixed to chassis.
That Pajero looks in a similar state as our Fourtrak did - I put a thread on here which might give you a few ideas. I was in the same position as you in having no experience welding on vehicles (though I'd had a mig some time before tackling the job and had quite of practice welding other things) Don't let that put you off though the biggest tip would just to get stuck in and don't be tempted to cut corners and leave a patch of rust behind - cut plenty out even if that means more work forming the replacement patches. You'll also find that compared with arc welding that you're used to you'll want to clean the metal back much more thoroughly - flap discs were a bit of a revelation to me having tried them for the first time on the truck - clean both sides of the joint too - crap on the back will come to the front and cause porosity in the weld if you're getting 100% penetration. Good luck it'll be nice to see how you progress with it all.
Will be looking at half bottle from engineering weld or BOC there the ones I have closer to me, see who has best offer, any advice on welding masks?Dont bother with small 'aerosols cans' last as long as a good fart, co2 is fine, will do your job and cost less. IMO.
I have aro shield also but cant be bothered draggin the cyl round