Not really, the only service we had was near Trillium lake, 2 or 3 bars of 4G LTE from Verizon and a little less from Sprint
It depends on where you go, do you know where you will be going? :)
Coverge is subject to LOS as Boones mentioned. Since there are several towns around Mt. Hood, should be able to pick up signal. But move around and check, signal quality will vary on location due to trees, ridges and valleys blocking LOS.
I frequently camp around trillium lake and I'm able to make cell phone calls and use internet. I'm guessing it may depend how far off the main roads you are. A cell phone tower typically sends and receives signals approximately 6 miles. These 6 miles are line-of-sight. The mountains do sometimes get in the way. I guess it really depends where on the mountain you are. If you are close to the highway or in a very popular tourist area you should be fine. (I use metro by T-Mobile)
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