Does this seem worthwhile, or a wasted trip?
Depends on whether you want to drive an hour to get it, or check out ebay and see the prices on there. If you want to use it, those are your options. It's worth it if it's worth it to you. Who knows if nintendo will ever release toon link again, and in all likely hood, if they do, it'll be a different figurine (like the smash mario vs party 10 mario). So if you want this one, and the drive is worth it to you, go for it =]
If you really wanted to collect amiibo you'd just preorder them because it's not like amiibo will be sold at reduced prices later. That saves you money, time and stress. Or, you could just enjoy them as they're meant to be.
You obviously haven't been paying attention if you think that's going to make it easy. Pre-orders are selling out within minutes, if they're offered. When they hit the store without pre-orders, they're selling out within minutes of the stores opening. Only reason why toon link and shiek are still kind of available is because they weren't really suppose to be released until the 13th, and some stores got a bit confused so now all of them are kind of releasing them when they get them.
As far as rarity goes, we have no idea how much they're making of each. The ones that are easy to get now are probably going to be the ones that stay common (the likes of mario, pikachu, etc will always be common, but that's still just a guess), all the new waves are going to be bought up within minutes of becoming available, be it pre-order or in-store. Only mess ups are letting normal people get a chance.
Please also note, OP and me are both in the states. The situation is frikin' insane here.