Some can get away with the front shaft length, you wont know till you get there. if you have a rear slip yoke that might make it too but im not totally sure, i never owned a blazer.
Make sure the spring bushings are good. For brake hoses g-van hoses will do with that much lift(if you wana save money)...i had them and then changed to russel baraided lines(better way). The steering will be a must, the stock draglink will be way too steep. I had the drop pitman and a raised steering arm(cheaper). Crossover is way better, if you have money for it. Shocks, a set of cheap skyjackers will get you thru..but better would be bilsteins etc.
The better way will always be more expensive, depends on your budget but better in the long run. What axles are you using..?..depending on the springs they might ride rough, i had superlifts and they were a little stiff. There are alot of mods to do here and alot of good guys to help.