Yes, packing for 2 wks in Europe in just a carry-on is do-able. Even if just for hopping on and off the train, it will be a less stresful experience if you pack lightly. I’d really try to do that. I didn’t for a trip to Italy in 2009, and I learned my lesson, so I only used a rolling carry-on suitcase for Ireland this past May.
Most of the tricks I used to make it possible for me to just use a carry-on for Ireland have already been mentioned, so I won’t repeat it all. But there were two things:
1. I brought what I needed for toiletries, in small sizes, and no more. (Your hotel may or may not provide them– I found that they usually don’t in Italy or Ireland– so plan to bring them). I can pack shampoo, conditioner, heat damage spray, hairspray, soap, several bottles of lotion, toothpaste, all my normal make up, deodorant, medication, and sunscreen in my “purse”– the giant tote I bring along with my rolling suitcase (the tote bag fits my purse inside it with my wallet, etc.). It counts as a carry on– and I had no issues fitting it all in. You could also buy what you need there– but then you’re paying more for it (exchange rate) and you’re probably only going to find it in full size– so you still need to make room for it in your luggage. I don’t think it saves you that much hassle & stres– and definitely not $.
2. I’m surprised more people haven’t mentioned investing in quick drying (aka, travel) clothes.
Check out REI and ExOfficio websites— REI and ExOfficio (and others I’m sure) make clothes designed to be washed in the hotel sink & then dried overnight on the hotel shower curtain rod, but anything synthetic (polyester, nylon, etc.) should be quick-drying, and thus able to do the same thing. Some travel clothing out there is hideous IMO (um, the underwear– so not honeymoon friendly! good thing a underwear doesn’t take up that much space!)– but there’s enough cute travel clothing out there to get by just fine in other ways. To wash the clothes, both of them sell packs of 50 laundry detergent sheets that are the size of a container of floss.
One other pointer: if the weather & your itinerary permit, bring casual dresses– they take up less room in your luggage than both a top and pants/skirt/shorts. I wore this one a lot in Italy.