Great idea and make sure the bike shop knows that’s what you plan. Cable and chain stretch and wear occur on every ride you take prior to your adventure. I also carry 2 tubes and a patch kit and a pump. CO2 is great for a quick fix to get you back on the road but you need to replace the CO2 with air as CO2 leaches out thru the tube in about 12 hours. For a longer rides I actually pack a spare tire. Depending on where you ride you might also think about a thorn proof tire and tube. Last year I had a flat from a very small piece of steal belted shredded car tire. Good luck on your adventure.