I visited the places mentioned in the title from 2/16 - 2/20. Started at Burney, drove south to Lassen, then north to Crater Lake. Verizon provided good coverage in the town of Burney but no cell coverage was available at Burney Falls State Park. Cell coverage, at least for Verizon, disappeared a few miles north of 299/89 junction. Heading south on 89 towards Lassen, cell coverage is available for a few miles then nothing further. Lassen at Manzanita Lake yielded nothing but snow and solitude. There was only a handful people there and most were walking on snowshoes, the only means of transportation around the park. Great place to be in winter if weather permits. The road trip from Burney to Klamath Falls was done via 299, 139, then 39. Cell coverage was pretty sparse around these parts until reaching Klamath Falls. From Klamath Falls to Crater via 39, 97, then 62 there was some coverage. I think there was a signal available at Fort Klamath but not much further. I thought I read somewhere on this site that there was cell coverage at the Rim Village of Crater Lake but my experience was to the contrary. Basically, there was nothing outside of satellite. The view was supreme but the walk on snow was difficult at best. Well, all in all I got the photographs that I wanted so I'm a happy camper. Hope this report helps anyone who is entertaining the idea of traveling to these locations. Oh, I have postponed my trip to Barrow, Alaska so no report will be coming soon. I may head up there in the fall season instead.