I did something similar, except i used a 10$ can of duplicolor truck bed coating (you could use any truck bed coating) in a rattle can. Survived one NY winter so far and not a chink in the armor yet. i cant say the same for the bedlinder i did with it, with this stuff sanding is KEY. the bed has been a horror i keep having to resand spots i thought i got because the stuff did not stick properly.
I did the bug guard, lower part (plastic stuff)bumper and my nerf bars with the stuff, no issues at all. since your sandblasting i can say that should be sufficent, sincei used a 600 grit foam sand block and got it done. I'd suggest a can of "prep all" you can get it from autozone near all the body filler and such. Great stuff for wiping things down.
