Kyivs'ka oblast' (Київська обл.) is a large area around Kyiv, full of suburbs. Most of the people live outside the capital, and every day they go to work or to study to Kyiv (hence be aware of using crowded public transport), while some minority of the people are the wealthier citizens who live in numerous cottage suburbs, which populate the forests next to Kyiv. Chornobyl zone is at a fair distance, 130km north of Kyiv, next to the border with Belarus. Road network is relatively fine around the region, since most major roads cross it: Kyiv-Warszaw, Kyiv-Lviv, Kyiv-Odesa, Kyiv-Chernihiv-Homel', Kyiv-Moscow, Kyiv-Kharkiv. The largest international airport in Ukraine, Boryspil, is located 20km east of Kyiv, connected by a broad highway, so unusual to see elsewhere across the country.
Zhytomyrs'ka oblast' (Житомирська обл.) includes its largest city, Zhytomyr, 150km west of Kyiv. Although less known, northern woods of Zhytomyrs'ka oblast' are also polluted with radiation after the Chornobyl disaster and sparsely populated. Southern part of region is a mix of forests and agricultural lands, with many smaller and larger towns across. It doesn't seem to be a tourist destination, rather serves as a transit area between Kyiv and the Western Ukraine.
Northern regions, where you can see sparsely populated countryside (sometimes abandonned villages), many provincial towns, some forests (less than in northwest, but more than in southeastern Ukraine). Main routes from Kyiv to Belarus and Russia go across these lands.
Chernihivs'ka oblast' (Чернігівська обл.), which includes Chernihiv and other smaller towns (Nizhyn, Hlukhiv, Baturyn, Putyvl') of historical importance - these were the headquarters of Cossack government in 17-18th centuries. Oblast' is neighboring with infamous Chornobyl' disaster area (a town of Slavutych, as an enclave of Kyivs'ka oblast' was built in late Soviet era for workers of Chornobyl nuclear power plant). But despite such the proximity, the environment is safe, it is even less polluted than industrial east regions.
Sums'ka oblast' (Сумська обл.), mostly agricultural land, in close proximity to Russian border. Largest cities are Sumy, Konotop and Okhtyrka. Less to see here.
Former Cossack land on the both banks of Dnipro. While Zaporizh'a was a base of Cossack army in 16-17th centuries, the historical lands where the cossaks lived with their families were here. Kaniv, Chyhyryn, Pereyaslav, Lubny, Myrhorod, Poltava remain full of history sites since then. The region is also a motherland for many famous Ukrainians as Taras Shevchenko, Ivan Kotl'arevsky, Nikolai Gogol' and others.
Poltavs'ka oblast (Полтавська обл.), often referred to as Livoberezh'a (ua:Лівобережжя, meaning the left bank of Dnipro). Mostly agricultural land, however some green belts cross it north to south, associated with major rivers - Sula, Psel and Vorskla. You will ultimately cross Poltavs'ka oblast' on your way between Ukraine's two largest cities, Kyiv and Kharkiv. Most people live in Poltava and Kremenchuk, first is rich in history, latter is rich in industry. A smaller city of Komsomol'sk, a satellite of Kremenchuk, was built in 1960's, nothing to see here except of the ferrous ore mine, one of the country's largest open pit, about 200m depth. You may also like to visit numerous smaller towns, such as Lubny, Myrhorod, Khorol, Dykan'ka to see some authentical Ukrainian lifestyle, as well as the village of Velyki Sorochyntsi, where Sorochyns'ky yarmarok (traditional culture fair) occurs annualy in August.
Cherkas'ka oblast' (Черкаська обл.), respectively Pravoberezh'a (ua:Правобережжя, meaning the right bank) features Cherkasy, the only large city on the bank of Kremenchuts'ke vodoskhovyshche (the largest artifical reservoir in Ukraine), historical towns of Kaniv and Chyhyryn, the town of Uman', famous for a large landcape park Sofiivka, designed for Polish landlord Potocky, and numerous villages swept across the hilly terrain.
Kirovohrads'ka oblast' (Кіровоградська обл.), in the past was known as Dyke Pole (literally, the Wild Field), a bordering land between Ukraine and nomadic Mongols and Tatars. Now it is the industrialized city of Kirovohrad, and vast agircultural lands anywhere around. The geographical center of Ukraine is located here, near the small town of Dobrovelychkivka. Otherwise, the region may be referred to Eastern Ukraine, not much to see here.
Central Ukraine is known for speaking surzhyk, so most of the people don't speak a pure Russian or pure Ukrainian, but rather a specific mix of both. Everything else is like elsewhere in Ukraine. Virtually anyone understands both Ukrainian and Russian. English is more or less understood by younger people (who study it) or by some adults of 25-35 years, who had work experience abroad. Don't expect any significant knowledge of English by officials (since they are prevalently older people, who had no opportunity, and often have no intention to study it). However most Ukrainians, even if they don't understand you, will respect you as a foreigner and make an effort to help you. Any other foreign languages are quite useless.