U-joints completely do-able by yourself with an open end wrench & a big "Chicken Press" but its no fun, especially if your in a water filled rut or snow drift at -30, it just takes time. Personally I have never changed one on dry hard ground LOL.
Same with the front spring, the biggest concern here is jacking on the frame to lift the wheel off the ground, takes a lot of blocking and the higher the blocking the more unsteady it gets. A big tip here would be to have your "blue wrench" handy for the U-bolts...cut them & use new ones... The old ones have been on there for eons in the harshest "oxidization environment you can imagine and can be a bear to unthread from top to bottom, second benefit is a lot less "under the truck time" with that makeshift blocking we often depend on.
All that being said I sure don't miss having to do either job anymore .