I was through this way in February of this year.
As mentioned, you will have no problems at the border. Transport along these coastal routes is quick and regular.
I highly recommend that you skip Togoville...it is a complete ripoff. If you do decide to go keep in mind that they will not allow you to take the local pirogue to get there but will have to hire one at a hugely inflated rate. You will also not be allowed to look around the village on your own but will have to have a guide at a rate of 10 000CFA (I'm not sure if this is per person as I was alone). If you try to haggle the price down you will be treated rudely. I balked at this fee and turned to leave and the rate dropped quickly, finally settling on 3000 CFA....still too much for what there was to see.
Aneho is a much more pleasant place to stay and to look around...a much better experience than Togoville.
If you stop in Ouidah beware the Oasis Hotel...the fellow there is a rip off artist. Unfortunately there is little choice about where to stay....just don't order any meals there without settling on a final price and definitely don't let him 'help' you set up a tour of town or organize onward transportation.
The stilt village of Ganvie was actually quite a pleasant experience despite the inflated tourist prices...I would definitely recommend it. Don't pay extra for a boat with a motor...not worth it...and if you have time, wait at the landing to see if some other tourist arrive to share the cost of your boat.
In Abomey I stayed at the friendly Auberge Mon Repos...clean, comfortable and great value.
I'm not sure if there is any point in you going up to Kumasi though it is a much nicer city than Accra. Trains don't run anymore.
You would be better to spend your time exploring all the forts and villages along the coast.
Elmina is a fantastic place...better than Cape Coast....and is an easy daytrip if you are staying in Cape Coast.