US-to-Canada Retirement Accounts

Hey all, looking to open a new individual retirement account as my current job doesn't have a 401k. We (myself and partner) are strongly considering moving to Canada however so I want to know what accounts would be the least pain in the ass to do that with (or to leave accumulating in the US). I don't make a ton so I lean towards a Roth IRA, but I know that can be a little more involved (declaring it a pension). Does anyone have advise on this/what's worked for them?