1. Only if it gets tangled/knotted and you're unable to remove the knot gently. Hamsters are experts at grooming and keeping their fur soft and fluffy; the most a really long-haired ham would need is maybe a couple of minutes brushing with a soft-bristled toothbrush every so often.
2. Hamsters don't need to explore outside, but it can be a nice adventure. Erin's Animals did
a video a couple of years back about taking hamsters outside. As you're in the US, you'll have more dangers than we have in the UK, so you'll need to be extra vigilant about checking the grass/area for snakes/spiders/other nasties if you do decide to take your hammy out.