My response is based on your stating that you are interested in Winnebago pushers in the 2004-07 range, 36-38'.
Winnebago made a lot of their pushers in the early to mid 2000's in that range. Journey's, Meridians, Vectra, Horizon's. The Journey's/Meridians were more entry level and the Vectra and Horizon was more upper line. They had 34, 36, 39 and 40' models. They were sturdy coaches with either CAT or Cummins engines. If properly maintained, they were fine rigs.
We owned a 2002 36' Journey DL for 8 years. It was a great coach. I never had any roof issues since I taped the roof-to-sidewall seam with Eternabond tape. It is pretty much a permanent fix for that seam.
All that said, I agree with the other posts. While my Journey was a great coach for the money, I would not focus just on Winnebago but look at all my options. Regardless of brand, how any used coach is/was cared for is the most important issue.