Wow, I just looked up the tour information, and I never knew it was so cheap. I'd say, if you have the extra time to come up a day early, go for it. There's a lot of stuff that they take you through that you won't get to see on gameday...and even for the stuff you will get to see on gameday, you won't have to deal with getting around crowds of people.
As for the seats, they are at least decent upper level seats (you can still see the scoreboard and it's on the home side). I'm sure you'd have no problem selling the tickets (I'm so jealous you're coming to the Pats game!), but I'm not exactly sure what the price ranges are for other seats.
Here's a couple of sites though (with interactive seating charts) that should be of some help.
Thanks for joining, and hope you have a great time at the game and in the city!
*edit* One thing I've noticed, and I don't know how I didn't pick up on this before, but sitting on the away teams side is much, much cheaper...even for lower level, near 50 yard line seats. If you're looking for great seats, but don't think that being on the Pats side would be a huge deal, I'd go that route.