There is no easy answer to the question above. Especially since you will be there in October during the rainy season.
Typically it is possible to go up through the Volta region to the north and continue up past Hohoe between the lake and Togo all the way to Yendi and then over to Tamale and then Buipe and Sawla. But between Hohoe and Yendi is a long stretch of very rough un-paved road that can easily take 6 hours with private transport on a good day during the dry season. During the rainy season it could be a nightmare, and it is recomended if you are taking public transport to split the Hohoe to Tamale into a 2 or 3 day trip. The highlight of this trip is getting very much off the beaten path in areas of Ghana where tourist rarely visit. Kyabobo national park is along this route also which is a great place to visit.
From Ho it should be possible to find transportation to Buipe without having to go all the way back to Accra, you would probably look for a Tro going from Ho to Korforidua and then from there to Kumasi. At kumasi you will want to get transportation to Tamale and hope off at Buipe if you have business there. Otherwise you should continue all the way to Tamale. From Tamale you can get a metro bus to Wa where you can jump of at Sawla.
The road from Domongo to Sawla is a very long washboard gravel road, and large parts of the north have a tendancy to flood in the rainy season, so I am not sure how easy it is to do.
Your best bet for the trip you are talking about is getting yoru own 4 x 4 transportion, if you share it with others it can become more affordable. PM me if you would like some help with this.
Also I would not suggest spending much time at the places you listed as there is really not much there unless you have business there, neither place is going to have much in the way of accomadations.
www.greenbugadventures.com