You would not need to roll over every month though. Look at the daily trading volume for CL @ CME: longer term traders are using the June and December contracts. This means that you would only need to roll over twice per year. https://www.cmegroup.com/markets/energy/crude-oil/light-sweet-crude.quotes.html
B/A spreads on the contracts that far out are a bit wide. You may take days to get a fill. You'd have to play with the ladder, and that can be unfun.