I have been to Malaysia and Pinang too. The best is to book a guided tour or rent a car and see hot spots of the island, like temples,beaches, musea, etc, etc. or buy a map and discover the gems of this beautiful island and Malaysia as well. Have a nice trip.
the best tip I can give is: rent a car or book a trip by Asia Travel (coach), they go to Cameron Highlands, book a hotel and see the Cameron Highlands, this area is much cooler than the rest of Malaysia. Visit a Tea House and drink a cup of tea from the Cameron Highlands Tea plantations. I did it.
I have never been to Rostov na Don but I should book a guided tour to learn more about the city because they know where to go and visit.
Well, Melaka is a nice city, past and present is there. I have no info about the hotels as I travelled by coach from Kuala Lumpur to Melaka city and stayed there a couple of hours.Perhaps wikipedia or Malaysian Travel Bureau can give you more info.