Bought my first 2wd Blazer - 6 lug question

[Ekliptix]

Well, I'm in the Blazer game now. Paid the fellow in Toronto and am flying the GF and I there in July to drive it 3,500km/2,200mi back home to Calgary.

2 Questions:
1) This Blazer has front disks (5 lug) and rear drums (6 lug). I'd like to have 5 lug in the rear too for aftermarket wheel considerations. What are my options to convert the rear to 5 lug?

2) I'm considering ditching the white walls for some US Mags Rambler wheels (20's). I'd like to be able to swap the 20" wheels from the blazer to my 72 C10 (5x5 or 5x127 bolt pattern). My question is if this 1970 Blazer has the same clearance and axle width as my 72 C10? The C10 can accommodate 295/45-20's in the rear and 255/50-20's up front. Just wondering if the Blazer will be able to handle this too. The Blazer appears to have a 4/5 drop or so.

Thanks!