Dee Godbolt

i have a 94 gmc k1500 suburban ,and I would like to know if i can swap out my rear axle assembly with one from a k2500 (same year as mine). what year front end and rear ends are compatible/interchangeable? Is it possible to swap out with something newer by chance? what engines can i swap out with that doesn't require a lot of modifications? I got the truck from my brother who passed , i just remember him saying "you can build a monster for less than you can buy it for" . I need all the understanding I can get , PLEASE HELP!!!!!!!!!!