I believe Derek has done the trek up there are there are some pics on his website (http://www.aussiecampovencook.com/
) of the trek and a couple of the campsites. On Alpine Way there are a couple of NP campsites which are fairly standard, no power, no firewood, watch for fire bans etc. Some have toilets. The Big4 at Jindabyne looks OK from the outside. There is another park that we stay in each year for a couple of nights on the other side. It's called Jindabyne Holiday Park. It has a good camp kitchen, showers and toilets are adequate nice powered and unpowered sites. I think Big4 has a pool. Both are on the edge of the lake.
Check for events on in Jindabyne and Thredbo if you plan on staying in one of the parks - they do fill quickly when CMC Rocks the Snowys (a roots and country music event) is on at Thredbo.
You can start the trek from either Thredbo (Fairly close to Jindabyne) or Charlottes Pass (not that close to Jindabyne).