At this point we drive an RV only on occasion. (Jim is transporting another RV from Indiana to Canada as we speak.)

But we have friends who drive RVs a lot. And we definitely plan to do more of it once we find "the RV of our dreams".

Recently, one of our RV friends asked us: "What's the best GPS unit for RVing?"

My first reply was "the Harman/Kardon GPS unit we currently own."

We love it. But in fairness, it's really not designed to accommodate the needs of trucks or RVs.

By that I mean... on our last RV trip through Minneapolis, we decided to swing a last-minute (as in: "There's a sign... let's go!") to the Mall of America. But we nearly lost our rolled-up awning, took out a few tree limbs, and beat the antenna up a few times when we veered off course and tried to get ourselves back on track.

Why? Because the GPS said to take downtown streets -- and most of them were down narrow (and low-clearance) side streets!

What we really needed was a GPS unit that showed "truck routes".

Ours is a 2004 Jeep Wrangler Unlimited, and we're planning to tow it behind an RV someday soon.

Here's what we've learned...