We do a lot of these type signs and fortunately sellers are getting the concept of less is more and actually paying for 2 and 3 colors but believe me, I've dealt with your type for more years than I care to remember...
Day's definitely taken your original panel idea and done a good job with it. The only thing I'd say is the number needs to be much bigger and that box moved up to allow another line of lettering beneath it.
As far as what to highlight? I think you're forgetting to treat the sign viewers as idiots, Jill. For Sale still needs to be the focal point to get their attention and the phone number second, so they can dial or write it easily. I usually do all the other gobbley goop in a bullet format, so it does busy up the sign too much. People can pull over to get that info, even though we know they won't and this guy is making a mistake putting all that on there.
Don't you love when the customer ignores your advice, shreds your layout and then asks, "That looks good, right?!"