I've done a trip to Jackson the last 11 years and skied there 50 or so days, here is my .02 on the "modest blacks" question. One of the great things about Jackson in my opinion is that so much of the terrain is visible from the lift, making it difficult to inadvertently get in over your head. For example both the thunder chair and sublette lifts run along a ridge on the north side directly above some of the steeper marked trails on the mountain. You get a bird's eye view of whether you are up to giving them a go.
I would suggest starting off skiing Larime Bowl, if you find the pitch too much or do not like the ungroomed areas i would not ski any of the blacks that are not visible fully from either the trail or the lift to give you an idea of what you are in for. If Laramie is ok with you I would suggest skiing the traverse under the expert chutes off the thunder chair to get a taste for whether you are interested in skiing some of the other black terrain. It is not a big commitment if you get in over your head and it is fairly representative of the conditions and pitch you will encounter on some of the terrain that is not easily visible and or more of a commitment. I will be out this year over MLK with my 10 and 13 year old this year for their first JH trip and this is the barometer i will be using before moving on to other terrain. Go as far as you can (near or past the tree line you come to) and pick a line, if you can ski this comfortably you could then give the split rock area off sublette a try. The trail maps show trails such as pepis and split rock but they are more just areas and kinda confusing the first time to find and ski. I like the east facing areas that drain onto rendezvous. You can also access some of this terrain from a traverse (blink and you'll miss it..) through the woods after skiing the often groomed bivouac once the trails converge and flatten out. If you enjoy this areanyou could do the Hobacks, they are 2,000 plus of vertical and can get real variable as you descend conditions wise with no exit once you commit so make sure the snow is good down low. If the cirque is groomed you could ski that area, but most of the other terrain around this area including the upper expert chutes is steep and requires you to make tight turns. Paintbrush is likewise steep and technical in spots, though not as steep as tower three or the alta chutes. Off the teton chair the area on the map shown as moran face is fairly similar but a bit steeper than the split rock and hobacks areas. For whatever reason it seems that teton is less skied, and therefore, often less quick to track out, than sublete. You could ski Kemmerer which is often groomed to give you an idea if you are up for the pitch. Saratoga bowl is tight trees and can also suck in the lower elevations unless there is good snow, you also have to be very vigilant to not miss the traverses back to the resort. I rarely ski après and Saratoga and will not be over in saratoga this year unless the snow really turns on and i get bored with the rest of the mountain.
Almost forgot the tram. Rendezvous bowl is similar in pitch to the area below the expert chutes off the tram, maybe even a bit easier snow condition wise. I would wait for a sunny day before skiing it the first time but the top of the tram is definitely worth checking out. Enjoy!
