Cheap 3.9 Range Rover

My H reg Range Rover has very bad rust on the sills, floor, door pillars etc, and it's not worth doing. I was trying for a body swap, but no decent ones have turned up. I've been offered a complete G reg Range Rover 3.9 for £700, which is rust free in the areas mine's bad, it's done 96,000 miles and had a new auto box 18 months ago. It's a real bargain as it's a lot better condition than mine. The rear seat belt mounts in the wheel arches look fine, but are there any other areas I should scrutinise for rust? I'd appreciate any advice. Cheers, Graham A.