Can I get a lift?

To all of you who are running in the double-digits: "You rock!" I am working my way up to a double digit run, 10 miles, before the 1/2 marathon. The first half of the race is apparently run on a steep trail, so once a week I run up a canyon with my kids in the double jogger. The two miles up are brutal, but well worth it because the views are beautiful. On the way back down it is obviously much easier except for the killer hill at the 3 mile mark. I have dubbed it "big bertha" due to the fact that my legs are aching and my chest is burning when I finally reach the top. My oldest daughter chants, "I think I can, I think I can" the whole way up. She is a great cheerleader. The only annoying thing about my run in the canyon are the comments from other people. I don't mind hearing "You go girl!" or "I am impressed!", because it actually gives me a little "lift" and helps me feel better about my run. The comments I find annoying are: "You're getting your workout" (you think so?), "They have the best seats" (referring to my daughters), and my all time favorite, "Can I get a lift?" I usually respond with a complimentary smile and nod, because it is the best I can give while I am huffing and puffing away. I should not really be annoyed by these comments, but I can only hear them so many times. Those of you with kids know what I am talking about. It is the same as when you take your kid(s) to the store and someone asks, "What aisle did you find him/her on?" How do you respond to that? I don't want to be rude, but I would like to have a response that makes people wonder if it was rude or not. Any suggestions?
Keep up the good work!