We stayed at the Regal Sun in March. The commute to the parks is not bad at all. In fact, what I have read says it takes less commute time from the Regal Sun than from some of the Disney resorts, depending on which resort & which park. You ARE on Disney property, just not at a Disney resort. You are also walking distance to DTD.
That said, we NEVER take out of park breaks in the middle of the day. To us it wastes alot of time. Not to mention that if DW left, she would NOT return to the park. We just rested in the park with a drink or ice cream when we needed to.