DS1 is 4 years old and DS2 is 16 months and we're about to leave for 2 weeks in Europe. We recently got back from a week in California and discovered that our 4 year old will not walk long distances. So we need some solution for both of them for this trip. We've considered the following, but don't have anything that clearly sticks out as a winner. Looking for any experience with any of these options - good or bad

1) Joovy Caboose or similar. This seems like a fantastic option because I could see using it at home too. However, we just tried this out in store and folds up HUGE! I'm worried about it fitting in our rental car with all our luggage and just overall being too cumbersome. Also the most expensive of the options at about $100.

2) A roller board to attach to our stroller. This seems like a reasonable solution though the reviews on these don't seem to be glowing. I like that we could tuck it out of the way when not in use and it shouldn't take up too much room in the car. None of the stores near us have one in stock to try out so we'd have to order it and try it out at home/return if it doesn't work. Also unsure if it would work well with our travel stroller (Summer Infant 3D Lite) or if we'd have to bring our regular one (Britax B-Agile) which is a bit sturdier. Also kind of pricey at $70

3. Get a second cheap umbrella stroller. This is a cheap option ($20) We could just carry it when DS1 doesn't need it and it wouldn't take up too much room. Mostly worried about it actually holding up for 2 weeks of heavy use with a 38 lb kid

4. Just bring a carrier and wear DS2 when needed. This is what we did in the past when DS2 was an infant. But now he's nearly 30 lbs and we're not sure if this is feasible. It also means we'd have to interrupt stroller naps if DS1 wanted to ride. Bonus is that we have the gear already so no extra costs.