I have been to Kutton on Santro / City / and Vezel. I personally think that corolla has a reasonably good ground clearance and you should have no problem what so ever in reaching Kutton. For rest of the Jaagran Valley, a 4x4 is must though. Care takers at Kutton rest house can arrange the same for you at reasonable cost. They can also arrange for a tour of the dam at the end of the valley.
On the other hand, Keran is a piece of cake for any car. You may find some patches uneven, due to land sliding but no issue of ground clearance. There are two rest houses at Keran by the river side 'Valley Trackers' (private) and Govt owned (AJK Tourism depy). Try to get your booking at the Govt one in case you decide to stay at Keran as it is right beside the river side and 'river side room' can also be booked. Other factor is the room rent as it is cheaper as well.
Please note that you can do only two things at Keran namely:
Sit by the river side and stare at the indian held Kashmir
or trek to upper neelum (Approx 4 KM track) which can easily be done in about 2 hours.
In my personal view Kutton any time over Keran !!!
