Things have been busy and in the week or so since I last read this thread (and made a mental note to respond to some posts when I could get on for a little longer), it has grown to 3 pages. So, my apologies for not responding individually and instead going with some general themes...
Why I want to carry in this situation... There seemed to be a few of these here. First, if I didn't live in a state where it was nearly impossible to get a CCW permit for a regular person I'd carry daily, and if I wasn't also a teacher which means I couldn't carry at work in most states I'd carry nearly 100% of the time. I am a strong believer in self-defense and in CCW, so when I legally can, I like to exercise my rights. I've been a victim of a violent crime before, I don't want to be again, so I want to carry when I can. I'm going to be traveling, stopping at travel plazas/rest stops, and stopping at gas stations and fast food restaurants in areas I don't know (i.e. where I don't know where the good and bad areas are), so carry is prudent.
Why not use martial arts or carry a knife... I don't have a bad back, bad ankle and bad knee because I'm overweight, I'm overweight because I have a bad back, bad ankle, and bad knee which limited my physical activity (the ankle is why the Army decided they didn't want me anymore, I developed the knee and back issues shortly thereafter and before I got fat, though I'm sure the weight has made them even worse). Recently (2 or 3 years ago) I've also developed neck issues as well. Even without the weight issues, these musculoskeletal issues will make any kind of "hand to hand combat" situation problematic- I won't be as efficient, I'm more likely to be injured (it doesn't take much to seriously hurt my back for instance - in addition to the already bad back and now the weight, a car accident some years ago and an injury breaking up a student fight this past year haven't helped) and if injured, it could be worse than it otherwise would have been. Add to that, I'm now 80 pounds overweight and this isn't a great option (though here in MD I am limited to carrying a knife and pepper spray). I also have high blood pressure, diabetes, and high cholesterol, so the serious exertion of a "hand to hand" situation may cause a heart attack (you can say that is just being dramatic, but I personally knew a teacher who died of a heart attack after breaking up a student fight, a fight is harder on the heart than many other forms of exertion). I may be turning 49 later this month, but I have the body of someone 10-20 years older.
Why carry around family members I know don't like guns... This one is a very reasonable theme. Partly, the whole wanting to exercise my rights where and when I am legally able. Partly, you don't know when/where something will happen. However, the biggest part is that I want the gun while traveling, and having it with me while there will be safer (from a theft perspective) than leaving it in the trunk or at the hotel. Hence, my desire to be as discrete as possible, that way I can carry without upsetting them for doing something they oppose as strongly as I support (or triggering an ugly debate when the intent is an enjoyable visit). I'm respecting them by not carrying at their home, but I do want to be able to carry while there.
As for why visit them if they are anti-gun, well, they are family, and I like them quite a bit even though we disagree on most political issues. Don't other people have relationships (family, friends) where you get along on most things, but have one or two things (political issues or candidates, religion, thoughts on their choice of life partner/spouse or other particular life choices) that it is better not to discuss?