If you are not going to be adding money, by far the easiest thing for you to do is open an RBC Direct Investing RRSP account attached to your existing account/bank card. You should be able to do this yourself online, or at the very least over the phone. You will then sell your mutual funds and buy an ETF, you can have a USD RRSP account at RBC if you like, or just buy the CND version of the same Vanguard funds. It is $9.95/trade, but I assume that as you are not a current resident of Canada you are likely not adding funds, so just eat the up front cost of getting set up and then let the funds appreciate. I recommend that you purchase one of the asset allocation/all in one funds by Vanguard, they self balance and you can DRIP them so you don’t need to pay commissions to re-invest, if you put all your money into this one fund, it will cost you a grand total of 9.95 until you withdraw in the future.
Option 2 is to open a Questrade account online, they will help you port over your RRSP funds from RBC to them, usually what happens when you port an account is the mutual fund is sold and it is ported as cash. You can purchase ETFs commission free with Questrade, but if you are not buying regularly commission costs should not be an issue for you.
You can sell and purchase any investment at a Canadian brokerage as a non resident as long as your are not living in a watch list country. I was not able to make any investments when I lived in Indonesia for this reason, no problem to do so when I lived in the UK or Colombia.