I went to saalbach a couple of years ago.
If you wanted to do some xc singletrack type stuff it would be worth trying a guide as the maps aren't particularly good and we found it difficult to locate that type of riding where bikes were actually allowed on (youre not supposed to ride on the main walking tracks). Did manage to find a couple of really good rooty single track type trails though and i am sure there would be loads more.
The bike parks aren't massive but are easy to get to.
Leogang is the better one and just over the valley from Saalbach. Its easy to get to by using the lift from Saalbach then a 20/30 min fire road ride to the top of the Leogang lift. From the top of there there is a good but moderately technical dh trail running down the RH side of the lift. i found it to be awesome in the dry but very tough in the wet as it is very rooty and pretty steep. Then from the middle lift station there are a few tracks down to the bottom. The official DH track is quite technical.the FR is good fun and is all rollable. and there is an easy wider track also with a few very small jumps. At the bottom are dirt jumps and north shore type stuff. Some is big some is good for practice.
Hinterglemm again is a 10 min ride up the valley on the road. There is the Adidas FR park. There are a few trails here but they are slightly easier than Leogang.
And there is another DH trail in Saalbach but this was not open when we were there so can't comment.
as for nightlife it was dead when we went but it was just before the main summer season. There are loads of places to eat though both at Saalbach and Hinterglemm.
Hope this helps and sorry if i have gone on!
Simon