Campsites may also still be available along the zone of totality, but they are booking up fast.

In Indiana, some campgrounds around Monroe Lake, near Bloomington, are already full, but campsites with a view of the eclipse are still open in a few other state parks, said Ginger Murphy, deputy director of the Indiana Department of Natural Resources. Minimum reservations are for that Sunday night and Monday night, she added. Mounds State Park, northeast of Indianapolis, for example, has some sites starting at $20 a night.

In Texas, R.V. sites at the Waco RV Park were still available for $37 a night. Campsite reservations at Texas state parks may be made five months in advance — meaning early November for the eclipse weekend — and normally start at around $20 a night.

With campsites such a hot commodity, some landowners are jumping in. Serenity Lewis-Lockhart, 46, a manager of H.W. Lewis Ranch in Leakey, Texas, said the property would open up to host about 350 guests in two different areas, mostly for basic camping but with a few R.V. hookups. Reservations for a basic camping spot start at $550 for two nights, with 10 guests maximum.

If you are planning to book more than one location to have a backup for bad weather, carefully check hotel cancellation policies, because they might be stricter for that period, warned Eric Hrubant, president and founder of the CIRE Travel agency.

Mr. Katsinas, the travel adviser in Tucson, also recommended looking for accommodations about an hour’s drive away from the path of totality, preferably in a big city, where more options are available. But if you do that, remember that traffic could snarl your plans.