Hello Andrew,
According the Ukrainian AIP you should make the first and final stops at international airport and as for me the UKLN will be the cheapest and easiest for you. Also there are some aviation enthusiasts. They are able to help you.
Then you can go anywhere except NOTAM restricted area
Also you can use UKLI, UKLU. Similar prices and traffic.
UKOO you can use if the rate of charges doesn't matter for you.
P.S. If you speak Russian please visit local forums at
www.forum.privat.aero
or
Украинский авиационный форум - Главная страница
I'll be glad to help you also
as for me UKLN will be the best for you by distance, traffic and rates
Contact me if you'll need anything else(contacts, airdromes information, flight-planning, etc)
Best regards,
Pavlo