Don't carry devices through customs. Buy them at destination. Get data from encrypted online archives.
Well, as far as I understood carrying devices might not be even that bad (easy to remove any social app and re-install after entering): with your name from passport, they go to Facebook or others looking for you. Very unlikely to happen (I cannot just imagine doing this for all people entering US...) but eventually if you declare on the form that you do not have a social account, then they check (for example upon secondary inspection) and find out one, you are in trouble. Moreover, for a frequent traveller what @mirimir suggested is not really doable.
It's pretty common for business travel. For different reasons, of course. Anyway: And don't have social media accounts using real name!
That would also raise red flags. I do have a Linkedin profile in my real name as my only searchable social profile. I carefully control who I connect with based on how US governments would view my connections. Use social media to your advantage and dont do something stupid like follow IS!S on twitter.
I have multiple hard drives including a portable SSD drive that I keep my OS on. I just put in a clean one when travelling to the USA.