I'll be in London in mid-September but can't help but want to visit Paris for a few hours to see the Eiffel Tower. I was looking at the Viator tours but I know myself and spending that much time on a tour would not be good. So I'm thinking of making a Eurostar train reservation myself that would give me 4 to 5 hours in Paris. Ideally, I'd like to get a hop on/hop off tour, stop at the Eiffel Tower, have lunch, get back on the bus if I have time remaining, then head back to the train station. Would this plan work?