Yes, MR said it was spotty, ER says she hasn't had much trouble (paraphrasing), it was reported that texts go through, and MR has a computer (unsure who has access/passwords). Let me see if I can find a specific link(s).
Also,
Spotty Cell Phone Service per MR:
Mark said he tried texting Dylan all afternoon
in an area with spotty cellphone service. When he didn't hear anything back by late afternoon, he went to Dylan's friend's house in Vallecito. That friend hadn't seen him.
http://www.denverpost.com/frontpage/ci_22108222?source=rss
Spotty Cell Phone/Texts Go Through per ER: (Nancy Grace Interview with ER)
GRACE: What`s this business about bad cell reception in that area? Was there bad cell reception? Did you have a problem hearing from him back on Labor Day, the last time he had visited his dad?
REDWINE: You know,
there is bad cell reception, but texts always seemed to come through. So while you can`t necessarily speak with someone on the phone...
GRACE: That`s true.
REDWINE: ...
it doesn`t seem like I ever had an issue getting texts from Dylan up there.
GRACE: You know, that`s true. That`s a very common experience. You cannot get a cell to make a cell phone call, but you can get texts in and out. You can even get texts up in the air on an airplane somehow.
REDWINE: Right.
http://transcripts.cnn.com/TRANSCRIPTS/1212/03/ng.01.html
Also, I believe MR has a landline phone. Have to find a link though...