Again, I think it is appropriate to have votes from CASps or plan-to-be's on how they think they should operate and opinions of others as replies.
After careful consideration of information at hand such as estimated costs and durations, site limitations/complexities and information obtained during interview with client or appropriate client representatives.
Present list of barrier removal items, prioritized, along with typical costs to the client; for the purpose of the client noting how soon each could be commenced given expected resources; use this information to develop a reasonable removal schedule.
Classify each barrier removal item within a few categories of time (orders of magnitude based on complexity and costs relative to the apparent capabilities of the client) e.g., within one month, six months, one year, five years.
Write each barrier removal item on a piece of paper; tape each to a dart; blindfold the client, who throws them, one by one, at a big calendar.
Some other method not listed here (including smart alec answers, which you are encouraged to post) .