Basically, that choice is correct. Currently there are five locations that accept public visitors.
1) Chengdu--Giant Panda Breeding Centre. The most convenient, the most accessible, the cheapest to access, and has the most pandas including views of young in the nursery. It has the most crowds though this can be mitigated by going early (07:30 to 10:00). Panda holding program has been discontinued indefinitely here.
2) Dujiangyan Panda Base. About 1.5 hours west of Chengdu in Shiqiao/Qingchenshan Village. This has the panda hospital and quarantines pandas incoming to and outgoing from China. There aren't as many pandas here but it isn't very crowded and a lot more green space.
3) Dujiangyan Panda Valley. Also about 1.5 hours west of Chengdu in Baima Village. This is the only place that currently has a panda holding program so for that reason, it does get visitors with cash to burn. It also has a 1-day panda volunteering program. Also doesn't have as many pandas as Chengdu but isn't as crowded and also a lot more green space vs the more zoo-like presentation of #1 .
4) Bifengxia Reserve. Near Ya'an, about 2 hours south of Chengdu. I believe still has a panda volunteer program but discontinued physical contact/holding program for now. Makes most sense to go here only as part of an overnight or multiple-day trip coupled with other sights in that direction (Emeishan, an old town, etc.).
5) Wolong Reserve. 2-3 hours west of Chengdu up in the hills. Newly rebuilt and reopened to public last year. Not a lot of data points on panda numbers that they've got there, but it's always been more sedate.

In your situation and if you are not a "panda fiend", it makes the most sense to choose Option 1 which you can do on your own/no guide needed--use taxis to get to/from and buy your own entry ticket. Total cost about USD 20. Option 3 would be the next choice, but if you do not want to specifically hold a panda (which I think is now around RMB 2000, then it's a long way to head to Dujiangyan just for viewing a dozen or so pandas. It's possible to get out to Dujiangyan by public transport (high speed train + taxi) and visit yourself (only the holding program requires prebooking which isn't easy to do without a tour agent intermediary). This could make sense if you want to couple it with a visit to the Dujiangyan Irrigation project or visit Qingchengshan (front side).

Pandas: don't like heat, so you must go early wherever you decide to go if you want to see them active.