Can't promise you the rear will be much easier. On my 78 the both mounting locations (front and rear) gave me fits with seized bolts. If you experience the same, you will need a longer reciprocating saw blade to reach into the boxed front fixed location to cut that bolt. I think I had to cut most bolts to get the old stuff out.
Upon putting in my rear Rusty's leafs, I had to use a piece of 4x4 (wood) on the spring, and then a couple ratchet straps around it and the spring to flatten the spring out enough to line up with the fixed mount location and the rear shackle.
I actually think my front was easier than the rear, sorry to tell you that. A sawzall, a cutoff wheel and good blades and discs are your friend. Don't cheap out on the blades and discs. Patience as well. I had to get this blade to finally get through all my bolts:
https://www.homedepot.com/p/Diablo-9-in ... /205426168
Also, get yourself some good cutting oil and apply it to the blade every once in a while to keep it cool etc.
I would not even fool with the u-bolt nuts, just take the cutoff wheel to the ubolt itself, careful not to cut into the tube wall of the axle though.