Trailing Arm Project

[low&slow]

I heard a lot of you guys welding your trailing arms together in the middle by either yourself or buying plates from various companies. My questions I have:

1. Can I remove the trailing arms from the truck without removing anything else?

2. Should I cut the plug welds, separate both sides, and clean out what rust may be there in the middle? Or not worry about it?

3. Can I just weld right down the middle on both sides of the trailing arms and grind it smooth?

4. After the welds are done, do I need to box it in or can I just leave the sides open?

I'm building my truck to maybe see some track time again. Not looking for low numbers and high speeds, but I know I'm going to end up welding the trailing arms sooner or later. Just trying to find projects I can do to the truck at home without having to buy pieces and parts.

5. Also, along with the trailing arms being out, what gauge of metal should I use to make drop blocks?