Originally Posted by
rota
Also an idea: you have this great airport of Bergamo near you, where you can use Ryanair at an absolut bargain. You can reach many summer destinations from there for like 20€/flight and check-in and either stay or just fly back home immediately (but I'm not sure whether leaving early may be a problem - but don't think so).
The OP said "near Venice". That's a 2-3 hour drive to/from Bergamo airport. Certainly not a day trip mattress run...
There are also hotels that check you out automatically if housekeeping finds an empty room. 1 or 2 extra nights is usually fine - booking a 3-week stay and leaving immediately might not work so well...