Thredbo/Jindabyne Garmin Connect maps?

We just got back from a week riding the trails you mentioned. You can get maps from shop in Jindy (wouldn't bother not the friendliest shop in the world- if your lucky you might bump into Paul the local trail builder out and about).
There is a good map on the trail head at Bungara - but ride all the trails anyway.
See the boys at the Crackenback resort they have maps and will give some good advice - ride all the trails and have lunch in cafe - good day out- recommend the lamb burger.
Cascades trail is a fire trail starting out at Dead Horse gap, no need for maps, its only 10km to Cascades hut so we rode to tin mines huts - about 50km return and 1500m elevation-a great back country experience - scenery is unreal-take plenty of food and water.
East Jindy - main trail to Tyrolean village is great, but do it a couple of times and take the side tracks- some are short and sweet others are longer, all seem to bring you back to main trail. Definitely recommend when you get to pinkys take a right and do the climb, this lead to missing link(?)and the Huff n Puff a sweet 1km fast switch back descent, this brings you back to main trail and you keep then do pinkys down which goes down to the lake.
Enjoy - its all good.

The four tracks you mentioned are the best the snowy region has to offer. Don't worry too much about maps (though the rollingground website is good) as Lake Jindabyne, Bungarra and Crackenback all have maps at the trackhead.
If you're staying in Jindabyne itself you can start/finish each day with the fantastic 8km Lake Jindabyne track; Bungarra is worth maybe 3 hours there, as is Crackenback. The Cascades track is probably the best in my opinion with a stunning array of scenery. The O&B to Tin Mine Hut is about 40km, but if you have someone willing to make the drive, you could do a point to point from Thredbo to Pinch Hut on the Barry Way. Wouldn't recommend doing it alone though as there is nobody around (and most likely no coverage) for kilometres.

Not sure how long you'll be there but the other tracks on the site look interesting and may be worth checking out. Rumour has it that you can get to the top of the Thredbo Flow trail on a management trail so wouldn't have to pay for the chairlift (but not sure if you're supposed to)

Have a great time there though. Make sure you get to Cascades as I think it's the best one there but they're all good fun!

According to the map from Dead Horse Gap. So a good full day ride. Note that according to the map, it goes in a generally downhill direction so will take longer coming back and some of the hills are fairly serious.