They shortened the schedule by 1 week and there are 12 "gaps" in the schedule of a week or two. There are 16 open weekends in the 39-week span of the 2007 schedule. IHRA needs 11 open weekends to completely avoid head-to-head scheduling, can get along just fine with 9, as they did this year. The open weekends contribute more to getting crossover Sportsman competitors than the Pro teams anyway.
The geographical criss-cross doesn't really affect the teams that much - very few stay in the vicinity of the last race any longer than it takes to test on Monday and very few drive directly to the next event unless it's back-to-back. That's why they have tended to base in a central location, like Indy, so they can get back to the shop between races when there's a week off. If you had races in Pomona and Vegas with a week off in between, for example, most teams would return home and then drive back to Vegas.
The geographical criss-cross doesn't really affect the teams that much - very few stay in the vicinity of the last race any longer than it takes to test on Monday and very few drive directly to the next event unless it's back-to-back. That's why they have tended to base in a central location, like Indy, so they can get back to the shop between races when there's a week off. If you had races in Pomona and Vegas with a week off in between, for example, most teams would return home and then drive back to Vegas.