We did it two years ago, too, but this time we didn't tent camp. Whenever we camp, it rains, and the Midwest didn't need more precipitation.

As we expected, it rained only once - a thunderstorm the first evening of the trip in the area around Connellsville and Uniontown, Pa., where we stayed the night so we could visit Frank Lloyd Wright's Fallingwater the following day.

The rest of the trip was bone dry.

Not camping meant we didn't have to rush past the scenery from one site to the next. In addition, we drove smaller - 35 miles per gallon in the Kia Rio we rented from Philadelphia to Denver, and an average 53 miles per gallon in the Toyota Prius we used from Denver to Los Angeles.

Gas didn't start costing more than $4 a gallon for regular until we reached Utah. In many Midwestern states, premium was cheaper than regular because they had more of it to sell - and quickly, before it lost its punch.

As people who drive an eight-year-old Volkswagen Jetta less than 100 miles a week (we take trains or walk) and never pay more than $20 for gas during the every-10-days visit to the station, it was a bit of a shock, Prius or not.

Driving for long stretches through other parts of the country offers great opportunities for discussion.

In the past, some of it involved arguing over travel directions. This time, we had "Hecuba," the GPS my family had given me for Father's Day, which did a reasonable job getting us from one place to another.

Hecuba is so named because of its annoying voice and its tendency to groan, "Recalculating," when we got off the highway for gas, lunch or Starbucks.

My wife has a subscription to this newspaper for her Amazon Kindle and was kind enough to read to me when I drove. The Kia had an MP3 jack (optional in the Prius), so we downloaded video podcasts of the evening newscasts and The Daily Show each morning on the first leg of the trip.

Except for my cell phone, a weather radio and, of course, Hecuba, I left most of my technology home. The best we could do for radio stations was usually National Public Radio; a couple of nights of "All Things Really Boring in Monotone" was more than enough for me.

So we talked about other things, especially our house and how we can make it more energy-efficient.

Air conditioning is the primary concern. The number of 90-degree-plus days in this area seems to be increasing, and the monthly bills are getting higher. The condensing gas furnace on which we depend for heat has a very high efficiency rating, though, and air sealing and insulating has made a huge difference in the winter bills (as has milder weather).

The converted attic that became our master bedroom has minimal insulation in the ceilings, and the actual sleeping area would be much hotter in summer if not for a small window unit that comes on in the evening and skylights opened for daytime ventilation.

As we drove, conversation turned to solar power again.

I hadn't forgotten that solar can be very expensive, and that, even with rebates, the payback time can be very long. The electricity-generating 2.5-kilowatt photovoltaic system we looked at a few years back would have cost $20,000, including installation.

Because high oil prices have caused more people to look at energy needs over the long term, applications for rebates are outstripping the amount of money available in many states, and there are long waiting lists for installers as well.

It doesn't look as if solar power will be getting less expensive soon, and the do-it-yourself solar systems available on the Internet - I was thinking we could start small and add later - are pricey and limited.

I'd like to hear from homeowners who have installed solar-powered electric-generating systems, so we can come to a decision and I can share with readers. Just e-mail me.