I suppose it depends on what other events they can get there. Concerts are a possibility, but they'd probably be really strict on the license for curfew etc given the surrounding area. The hotel could work but they'd probably need to work hard to convince travelling fans it's worth the premium to stay at the ground. That said, for early Saturday kick offs, they could do good business (fuck, might even be worth the opposition team using it!). I'm sure they have plenty of ideas floating around, but there's a lot of competition in London that will want the same events etc.
That Premier League rule about not using 2 stadiums is a bit of a joke. If the opposition team isn't arsed about it, I can't see the issue. I know it's probably for fairness so all 19 games are in theory held under the same conditions, but there's never level conditions at any game. Injuries, the weather, European games all change the variables.