We enrolled with EZPass specifically for our trip down from Massachusetts to the Fort this past April. We received two transponders. One is strictly for when we are driving the TV only, and the other is for when we were towing our hybrid trailer. You only use one at a time, so when you're towing your camper/trailer, you would need to keep the one just for the vehicle in a FOIL LINED WRAPPER (the wrapper they arrive in when they mail them to you works) so it won't register when you pass through the tolls.
Considering they don't charge for the actual transponders, it's just a matter of keeping a small minimum balance (like $20.00) in the account they draw from, I think they are well worth it. I will warn you, however, one thing that is in the fine print which we didn't read (admittedly stupid) and weren't made aware of (of course) is, they can (and will, without notification) raise the minimum balance depending on your usage. I was quite surprised when I called to find out why my account had an additional $25.00 taken out and I was told this was their policy. (Ours went from $20.00 to $45.00 because in addition to the trip down to Florida, we use them to go to New Hampshire and Maine quite frequently. I was told that if our usage drops for a period of 30 days, we can then call back and have the minimum balance dropped back to the original $20.00).
I can't even begin to tell you how much time/aggravation it saved us, both on the way down to the Fort and on the way home (especially through New Jersey). In some spots, the lines for the tolls were CRAZY long, but we were able to just zip right through with no problems.
IIRC, they are valid all the way down through to Virginia.
We found them so convenient, we added another (at no charge, as I believe you can have up to 4 transponders on a single account) for my DH's car.
HTH, and have a great trip!!
