It really depends on your particular Advantage Plan and your travel intentions. My Advantage Plan, an Aetna PPO type, covers me nationwide and gives access to any Medicare-qualified provider. The reimbursement rate is the same for their network providers or an out-of-network provider who accepts Medicare (in other words, they pay the Medicare rate to both), so I have no problem at all getting medical care wherever Medicare is available. But not all Medicare Advantage plans are like that, so you need to investigate yours. If yours is an HMO type, you need to think carefully about the number and location of its HMO providers vs your travel itinerary.
Traditional Medicare (Part A + Part B) gives you more assured access to treatment wherever you go, but almost always provides less benefits than any Advantage Plan. Terefore there is a tradeoff between what you get and accessability.
