I have an 18-200 that I use on my crop sensor camera. I just work with it.
I use Nikon's 18-200VR2 lens on my D7100 (and had used it on D50 and D7000). When I want a wider view I just do a panorama sequence. I turn the camera into portrait mode (vertical) and take a series of photos with decent overlap, then merge them into a panorama. Lightroom (and Photoshop) have features that do the merge, and I've also used an after-market tool called Autostitch (which does a nice job, too). Although many folks here say one must use a tripod to get good panoramas, I do all mine hand-held, and they come out just fine.