Need help to chose the right GPS

In the Garmin line-up, requirements (F) and (G) point to the Nüvi 7xx or Zümo ranges.

Not just F and G but all of those point to the 7xx line. It's the only nuvi that does multiple point routing. Your only issue is going to be low clearance, as it has to be added as an external POI set by someone who has uploaded a file to a site like this. As such is will NOT be used when calculating a route. Also, it is only as accurate as the person who created it. The best thing you can do is to create a route then search for low clearance POIs along it (searching along a route is a built in feature of the unit) and if you find any that are too short then you need to figure out on your own how to go around them and add some points to the route to do so.

Also be aware that many of the users here have Garmins, so you'll probably get a lot of recommendations in that direction.

I got mine 3225 for Christmas, played with it ever since, very simple to use. I love it, you might try it to see for yourself.
Q.RV friendly (locate Campgrounds,dump stations,low bridges , gas stations and so on)
A. You can download POI files here

I would go the Garmin nuvi 750 then. Multiple routes, easy to use, voice, etc. I have the 760 which has Bluetooth and love it, but if you don't need bluetooth, the 750 should be great!

I think you should consider the traffic information capabilities. It really is only effective in fairly good size cities and will not help in remote areas or open country. But when you are going through a city pulling a camper it could be a great help to know where traffic problems exist.

Garmin Nuvi 7XX would be a great choice with or without traffic.

I like the traffic, too. I opted to buy the MSN and really enjoy it so far, and enjoyed the TMC trial that came with my Garmin 760. It takes a few hours to let th MSN Direct to run and load everything into it, but now it is up and running fine.

My wife and 11 yr old daughter stole my GPS from me yesterday because they wanted to see movie theaters and movie times that MSN Direct displayed. The gas stations were right on, too. I now have my GPS back, thank goodness hahaha

I listen to traffic reports and checked them against what the MSN Direct was stating, and it was on as well.

Some like the TMC, and some like the MSN Direct. TMC Traffic comes with the 760 with a 3 month trial.

I've used Garmin, TOMTOM and LG GPS units. Seems like The Garmin 7xx series is your choice based on what you are looking for. However, be prepared to pay as well.

Based on your criteria, the LG LN790 or 740 is a great unit at a more reasonable price. TMC comes with both LG models that have the 90 day free trial. With over 7 million pre-loaded POI's, you can't go wrong.

Good luck!

Thank you all for the swift and informative answers, I will do some homework and get the "ONE".