We were in 2015 , we loved it , stayed 7 days , sorry not from US so can't comment on flight costs .
First 3 days we stayed in a guest house by Plaza Trinidad , with local family . Nice family but it was a bit pricey for what we got . Location was awesome , plaza Trinidad is full of locals chatting , dancing , etc in the evenings, surrounded by few cafes. Some tourists too so it didn't feel overwhelming .
We went looking for ATM at night as we needed cash and had to ask a few people so it was clear we were walking to get the money :) We felt safe . Not Thailand safe but South America safe . As in watch your back just in case . People were very helpful .
Then we moved from old city to new part and stayed at holiday inn express . By that time we backpacked Chile, Bolivia and Peru for 2 months staying in pretty budget ( read basic ) places that holiday inn was prefect with aircon and a swimming pool :)
Highlights ?
Volcano !! Google totum volcano , yes it's super touristy , I was 50/50 before we went , but it was such a unique experience , we both loved it . We still talk about it .
Old city was cool , very colorful .