Went to Alpe D’Huez last year and stayed in Belambra Les Bergers which is cheap self-catering accommodation. It was very basic and a bit sparse in terms of cooking equipment, I think we had a microwave/combi oven (impossible to even cook a pizza in!!) and a 4 ring hob and that was about it but we struggled through! I’d go again if I was just going with the lads but don’t think the missus would be happy there haha!
I loved the Alpe D’Huez area for the biking though. I preferred the enduro runs there which were much like the singletrack you find in the UK but just fantastic sections all downhill for about 8km rather than 80m! If you stay in Alpe D’Huez there is one lift up out of the resort which is the main DMC gondola and then from there you can cycle down into Oz en Oisans. I definitely wouldn’t rule out staying in Oz because although there will be less non-biking activities to do, you are more central in terms of the biking area so could go either way up the valley rather than in Alpe D’Huez where your at one end of the area.
One thing to be careful of is the weather, we got stuck over in Vaujany one afternoon when the weather quickly turned after lunchtime and the lifts were shut during a downpour. They reopened it at 4.30pm but only to the mid-station which meant we had a 12km cross country route to do to be able to get back into Alpe D’Huez valley.
If you need any more info give me a shout and I’ll try and help