I would get at least 80 Dungeoneering on the account for a chaotic. Other than that I wouldn't get the Prayer up mostly because people here on Sythe can be very cheap when buying accounts because they always think it's going to get recovered back. And people tend to bid very low...I had to sell an account with 93 dung 95 prayer, 99str, and 80 attack for 75m :\
Also may want to try to get some charms for a higher summoning level, not essicarily do the summoning yourself, just the charms so the buyer has the option.
Good luck though.