What's that Title?

Ok. Here we go...

There was a family film I owned on VHS (I'm assuming this title was a direct to video release) in the early 90's (or late 80's), released by the same manufacturers that released titles like, "The Buttercream Gang" to VHS.

Plot: 2 young boys are orphaned after the death of their mother, and set out to trek across the country in search of their 'would-be' uncle. Along the trip, the boys encounter a young woman who shares an amazing resemblance to a lady found on the side of a rasin box. Once the boys reach their presumed uncle, they discover that this person is no relation to them at all, and 'uncle' was simply the term their father used to relate his friend to these kids.

That is the majority of the plot that I can recall. Anyone have any idea what this movie may be? I thought the woman might have been Susan Sarandon, but checking her filmography, I found nothing to support that theory.