Copper Harbor has trails for all abilities (flowy and mellow to "you ride down that?" crazy). There is quite a bit more climbing there than locally but the climbs aren't steep on the easier trails. Trail surface is generally dirt with river rock mixed in. There are some section with slick rock and jagged rock outcrops but those are typically on the blue/black trails. You'll have a lot more fun on a trail bike vs a XC full squish but either will work fine. A DH specific bike will be too much bike for most trails. Never been to Spirit Mountain; hope to change that eventually...