hi G.!
your posting made me laugh; i'm in exactly the same boat. my nearly-3 yr old Wild Man will nap, IF all the planets aling, around 2; my daughter, 13 mos, naps at 930 and usually again around 3. so yea, getting out is always depriving someone of a much needed nap, and me of even more of my slim portion of sanity.
i got into a bad habit of doing driving naps w them because my son would get so nutty in the afternoon if the baby distracted him or whatever else kept him too wired to nap, and then he would also sometimes fall asleep on the couch, relegating me and the baby to the bedroom for 2 hours, in our 1 bedroom apartment! so if i threw them both in the car at 2, they would nap as long as i kept driving. $50 a week in gas!
so i bought a wonderful side-by-side double stroler by Baby Planet, with fully reclining seats. it is VERY heavy with both kids in it (they weigh 35 and 23 lbs respectively) BUT, again, if i get them out to play at lunch time to the playground or the book store for a good long time, i can put them in this stroller and walk VERY slowly for at least 90 minutes, gab on my cell w a headset, and get a major workout all at the same time. the stroller cost $300 but was well worth it in gas alone.
the only other thing i would say is, no one's going to perish from a missed nap. in an ideal world they would nap together, which i can maybe once a month get them to do again w a big lunch time workout outdoors, and then i (you) can also take a nap or just have some peace and quiet. but tht rarely rarely rarely happens. i do think i will have better luck when the local pool opens for the summer; i would suggest that to you. give them a big breakfast, a small snack, go for a long swim or play in the sprinklers at the playground INSTEAD of lunch, then when they're really spent, give another small snack or even much deserved ice cream, and try to nap them, that should work!
good luck!