I have been to auli along with chopta-tungnath two days back(4april -8april) below is the itinerary u can follow(latest prices)
1. take a overnight bus to haridwar so that u reach early morning around 2.45 am.
2. there is a bus which u will get from haridwar bus stand(opp haridwar junction) to joshimath at 3.15 am(GMOU bus vishwanath travels) cost - ₹400 /person, u will reach joshimath max by 4.30 pm as there is a lot of construction for chaar dhaam yatra going on.
3. stay in joshimath, maybe u can book GMVN guesthouse dormitory in 200/bed, i stayed there it is quite good with geyser also, visit local joshimath (shankracharya math, narsing temple).
4. next morning go to Auli by ropeway cost - 1000/person(but its all worth it) it takes 22 min to reach auli. Timings - first cable car - 9.20am last - 4.20 pm.
auli is full of snow this tym... for better views u can trek upto gurson bugyal(hardly 3 kms trek) from auli.
come back to joshimath and stay for a night.
5. Next morning direct bus to haridwar will start at 4.30 am and will take 13 hours.
6. from haridwar to ur destination.
Auli itself is a tourist place and you can visit places in and around it with the help of local taxi . Reaching Auli through Ropeway is very good idea . Then you can reach Auli by taking a bus to Rudraprayag and then book a taxi to Joshimath . From Joshimath you have Ropeway that will take you to Auli .