I am thinking of buying a GPS for my Class C RV, that would have text-to-speech and dead reckoning capability. I am find that all the commercialized information out there is a little over bearing, and have decided to ask those who have them. I have NO previous experience with a GPS unit ,other that what I have researched. What RV GPS units have you gents and ladies found to be more productive, and why? From what I understand, a RV GPS must be a Trucking GPS, to allow for avoidance of low bridges and propane restrictions. SO, I am reaching out and asking..... what do you have, what do you recommend, and what to avoid??????