OK, well I guess there are a few different approaches to this. One way would be boot-only distro from live CD as already suggested, and another way would be to have an encrypted partition or whatever.
If you're going with the latter, then i'd definitely suggest employing some anti-forensics techiques (it will make the feds rage at the very least), for example you can whitelist known serial #'s for all USB's and HID's so when they attempt to use their forensics tools (not for actual hard disc forensics ofc... they'd just image the drive itself for that) it can just zero over the contents of the drive (i.e. the drive w/ their tools on with 'trolololololol' or whatever) - int 0x80 did a pretty interesting talk on anti-forensics which covers this method and also a bunch of other methods to make a forensic investigation far more complicated for the feds to deal with. You can find this here:
https://www.youtube.com/watch?v=-HK1JHR7LIMPersonally i'd say a live CD is probably the best option of the two, but if you have data and tools that you need to store or need for each use therefore go with the latter, you really do need to take more precautions. Make sure to have a copy of DBAN (
http://dban.org) laying around ready to use at a moment's notice.. i've heard of people setting things up with electromagnets so that a switch gets triggered when their door gets busted open and it fries the hard drive or whatever (not sure how effective this would be.. I'm sure they may still be able to recover SOME data as opposed to zeroing over the drive a bunch of times which would pretty much remove everything) - another thing you need to take into account when using an encrypted partition is the risk of cold-boot attacks (where they will freeze your RAM with liquid nitrogen so they can recover the encryption keys stored via volatile memory at a later date) - i've heard cold-boot attacks can be circumvented by attatching COCKodile clips to the RAM, but i'm not sure how this works exactly.
Also, if shit *DOES* hit the fan then it would probably be best to already have a backup plan in place. i.e. travel arrangements for a country with no extradition treaties and means of getting there undetected. Obviously the amount of necessary precautions are dependant on the riskiness of the situation.
Some of the info here might interest you, its from a 2600 submission by nachash - I'm guessing many people ITT have probably read it already but if not there may be some useful stuff here too. It's more geared towards running a tor hidden service but has some related stuff which can definitely be applied to these kind of things, that can be found here for those who may not have read it:
https://pastebin.com/raw/GrV3uYh5one last thing that should be taken into account is that in certain countries (I know in UK for sure) it is illegal to not hand over your encryption keys if ordered to do so by a court (and you will be sent to prison for refusing to do so) - I guess there's probably some similar rule in USA too, under CFAA or something similar. At that point I guess you'd have to make the choice whether what they'd find if you didn't hand over your keys would warrant a worse sentence than refusing to hand them over.
