What version of DW are you playing? Stock, DWX, LWAMI, or RA?
Stock- a great way to learn the basics (this includes all platforms). Campaigns tend to give you the option of which type of platform you want to drive for the whole campaign.
DWX- Mostly a buff on the 3D models but always read the install notes.
There isn't that much difference between Stock and LWAMI but you'll want to concentrate on what kinds of missions and campaigns you snag. LWAMI also has a larger selection of platforms and nations to play against. LWAMI also attempted to "even up" the multiplayer experience a bit by nerfing the sonar displays slightly, but its also a good single player mod.
RA is a bit like going to Grad school. RA concentrates on multiplayer and also provides a different perspective if you're tired of playing on US platforms. It isn't single player friendly (there's no where to hide) unless you've had a LOT of experience in DW but the 3D models, playable platforms, and nation database are really good.
RSR is great, but RSR has you running multiple platforms. So, I'd wait on RSR until you get some experience with all of the playable platform types (FFG, SSN, Helo, P-3). Single missions tend to concentrate on "shoot 'em up" or the old-timey "track 'n trail" surveillance missions from back when I wore the silly hat during the cold war.
Sonalysts kinda used the stock campaigns to showcase the new features in each game. With DW, there were a lot more playable platforms than before so expect to be doing something in the FFG, the P-3, and the helo.
Just my recommendation, but stick to one platform until you get tired of it.
Stick with single missions for a while and start learning how to create your own missions in the editor. Then, switch to another platform and get some experience with it. Check the campaigns and the single missions here and at subguru.com.