So right now I have about 2000 points of space marines, and while i love it, I'm trying to build a very anti-vehicle army. Essentially the only vehicles i will be owning will be drop pods for my tactical, and a bike squad (but are those REALLY vehicles?

)
I just need some help flushing out how to make it well rounded enough to not be completely destroyed in my games, although i do play mostly for fun. A few of the things my army feels like it is lacking in is:
long ranged firepower (i only have devastators for this)
fast mobilization (I do have assault/vanguards, so that might suffice)
AV14 killers
Any advice to help cover these weak points without succumbing to lame sauce vehicles?