First of all, migration for question older than 60 days is disabled. If you are considering any large scale migration, you'll need to follow the advice on: How to migrate old questions to a new graduated site.
Now to the issue at hand:
- The Travel community must first decide if you want [outdoor-activities] or not.
- If you decide that you don't, The Great Outdoors community must decide if they want them.
- Only after both communities are in agreement, you should start discussing migration.
Generally speaking, if you don't have a very good reason this wouldn't be a good idea. A very good reason would be that you get a lot of [outdoor-activities] questions on Travel, and they are not treated well. If they are on topic and sufficiently answered, what's the point of sending them elsewhere? And if they are off topic, but you only get a few of them, just close them as off topic and point to The Great Outdoors in comments (or flag for moderation attention and ask for them to be migrated).
Even more generally speaking, during beta you can't really afford sending away questions that are on topic for you, be a bit jealous of your site. In the unfortunate even one of the two site's gets closed, you can discuss migration then, as jonsca mentions there's precedent.
Since this whole discussion concerns only 12 questions, of which only one is closed, I don't really understand why you're even discussing migration.