How much time do you spend riding, on average, in a given week during your prime riding season? We'll set aside those winter months that you don't want to think about and go for the prime time average.
Conversely, how much time would you like to spend riding each week? Now, don't be unrealistic here and say you want to spend 24/7 on the bike. Just think about if you had all the time you felt necessary to ride until you needed to rest, and what you could consistently maintain. What would be ideal?
That second column is one that I really doubt we'll see too many low numbers, but what is truly realistic?