Man these things are cute. So here it is:
BR Mjolnir x2
Chucker Oles
BR J100 RV
Merc Sniper
Raiden or Kage BA
-449 points.

I choose water for my terrain, place it up near his DZ and scatter it around the map. My Mjolnirs can get up in his face on turn 1, and even charge unscreened stuff put on the edge of his DZ. I know, I dont have base screeners for my own arty, and if the opponent is playing masses of ATV's (very likely) Im pretty much ####ed. Chucker can get up there too, and all of the mechs can dance around in the water up in his face while sniping out artillery, they can even afford to soak in a few shots and then retreat in 1 turn to get repaired (28 inch walk is nice.) I just want to know what to do to protect my own artillery and RV, which are pretty much cannon fodder and ATV feed as of now. Thanks!

One option is to forget the artillery altogether. Treat your force like repairable, shallow dial SCs and run under their arty.
Another possibility is to use the BR AgroMech Mk II (if rapid strike is your thing, but w/ grapple as well for less points), or what I like is BR ConstructionMech MkIIs for the agility and brawling and great heat dials. I use to run an army like yours with these but with 300 pts. I could only use 3 (x79) and have enough left for support. At 450, you could even try 4 which would be 316 pts., leaving 134 pts. for support. Charge with these in rotation, with some charging and some running back for repair. FUN! And drives the smirk off opponents face real fast unless they bring a fatty, in which case you kill everything else then run, or use the multiple charge chances to wear it down, which is more risky.