SiliconCruiser

The cruise lines that cover Alaska, mostly Carnival brands like Holland America, Princess, and Carnival are U.S. based businesses that must offer accessibility in compliance with ADA. And they often own the lodgings in Alaskan land/cruise tours, and like any public lodging in the United States, they too must offer accessibility in compliance with ADA. Train transportation must also be ADA compliant (after all, Alaska is part of the United States 😉.) The one caveat would be the excursion operators at the Alaskan ports. Many do not offer accessible vehicles and are not required to. You'll want to check before you book any of them. Same with the excursions offered by the cruise line (since many are through the same operators.) If the excursion is accessible, it will usually be noted in their literature.

I would avoid ride sharing services, unless your traveling companion can lift and place the scooter into the vehicle on their own. Uber/Lyft drivers can come up with all sorts of excuses to not assist you. The drivers could care less about ADA compliance, though Uber and Lyft feign compliance with "guidelines" for drivers. We find regular airport shuttles (they have vans with motorized lifts) to be far more reliable and consistent with pricing. Many of these shuttles also go to cruise ports. US airlines are better trained and are pretty consistent about transporting and gate-checking mobility devices so that they'll be waiting for you right outside of the aircraft. Your experience on the ship and disembarking at ports may vary depending on the ship's crew (not necessarily consistent throughout a cruise line.)

We also experienced the same thing in Singapore. When we got down to baggage claim, we saw a female baggage handler struggling to try and push the wheelchair with the wheels locked. I screamed "Stop!" very loudly across the room and she stopped. Fortunately, the only damage that was sustained was a bent bolt. We filed a claim immediately and received a repair authorization. (Changi airport in Singapore uses a centralized damage claim area for all of the airlines, so you don't have to deal with the excuses/lies from the airline employees. You should not deal with airline employees in Singapore.)

Yes, it is not a problem. At least not in the U.S. and some of the more responsible airlines for international travel. My wife uses a transportable motorized wheelchair that uses a Lithium battery. With the exception of China Airlines, the battery has always remained with the chair in transit. Unless your assistive device has shock absorbers, you'll feel the bumps with both. Wheelchairs turn a tighter radius. Motorized wheelchairs use separate motors for the left and right drive wheels enabling much more agility in maneuvering crowded areas. Scooters are cumbersome and inconsiderate passengers will often leave them sitting in the hallways outside of their staterooms, blocking the hallways. I have moved a few of them (yes, I know how to move them without the key) so that my wife could go by in her wheelchair. Both scooters and wheelchairs will fit through the doorways of ADA accessible staterooms.