you'd best check colorado law. most likely, you remain a resident of colorado even if not physically present until you have residence (or intent) established elsewhere.
you can have absentee ballots mailed anywhere, but you need to check with the state registrar on requirements. texas now emails ballots and envelope pdf files - print 'em out and mail 'em in.
you can file tax returns from outside the state even if no tax due to show intent to return.
for health insurance, you need a policy with worldwide coverage including repatriation.
you need to get all your banking/financial accounts set up before you set off, usually no way to open us-based accounts from outside the us. need a us address......banks won't send credit cards outside the us. (one exception is navy federal, they accept foreign addresses and will post cards ex-usa)