I have used a Magellan GPS for the Sport Trak (2006/7?)came out. Seemed a bit expensive at the time but it did just what I wanted. I had been using several GPS's since they first appeared and even used some in a minefield (Yep) during my active duty days.
I am on my forth model now 610 and it works well for navigational purposes in the Jeep. It was a very good secondary backup for my trip across America in which I had all my routes planted. I used a Garmin Nuvi with an SD card as primary for a bigger screen.
Screen size I think is the first thing you will need to consider. Especially if you are driving and trying to navigate at the same time. We still missed turns while talking and distracting each other during that long trip. The Magellan 610 will not do road routes like what you may want, it is designed for off road and hiking mainly.
There is a computer program that you can use in conjunction with the handheld products called Vantage Point. Laying out trips and routes there are pretty simple once you get the hang of it. Then it all gets transferred to the handheld unit. Swapping info back and forth is pretty much a easy task.
I too thought of a larger unit Magellan TR-TRX but I have used these smaller ones for hiking/sightseeing and Geocaching. Sized just a bit larger than a flip-phone.
Jerry mentioned the lack of trails but failed to mention that many of the trails are added to the GPS as you drive and label them. Folks then download the trails to Magellan and they get put on the latest, updated maps,; as I understand how that works. I almost purchased on for TAT adventure but I decided not to because I didn't want the trouble of learning a new system to interfere with my travels. As I look back on it, I think the redundancy might have been a good mental insurance policy. As it turned out we did just find with what we had.
During the Trans America Trail (TAT) we traveled over 5500 miles and I never had a lick of trouble out of the Magellan or the maps. I will mention too that all the road names aren't what you might find when you get to a spot. (Garmin seems better at this) Keeping charts and maps up to date is a hard job for any organization. So, I can't fault them there.
What you want to do with the GPS is going to drive you toward the features you need though.
Ease of operation