Disney Quest is a large video arcade. How much time you wish to spend there really depends on the person.
I could easily spend 5 - 6 hours there but then I am a huge video game junkie.
However on average I typically spend about 3 hours each time I go.
Teenagers will want to spend more time than Adults and very young children.
We typically go after dinner. Arriving around 8pm and we stay until 11pm or so, by then we are rather tired from our long day, so we go back to the resort to sleep.
I hope this helps.
Cindy in NY.