Since I did this route by van with a german traveler and I haven’t used public transport, I could not report the experience. I took this report from Sevi Ioannidou, with her permission, in West Africa travelers group on facebook.
She took an STC bus from Tudu station in Accra to get to the border at Aflao. She thought that this bus has scheduled departing times so she didn’t go for the mini buses. But actually they were waiting for the bus to fill and that took around 1,5 hours. The ticket cost 65 cedi plus 20 for her bags (7,3 USD).
They arrived at Aflao after 3,5 hours. The bus station at Aflao is very close to the border so she crossed the border on foot, although many people offered to help her but she kindly refused since it was doable.
On the left side is the Ghanian immigration and right side Togolaise. She got Visa on Arrival, single entry for 25.000 CFA = 40 USD. She filled a form, answered questions and got the visa in 15min. They spoke English. When she finished with health office, immigration and customs she was already at Lome.
From the border she took a moto-taxi for 1000 CFA (1,6 USD) to a place called Tcha tcha. Actually she want to recommend this place: you can find it on maps as Villa Tcha tcha and it has a nice garden with cafe / restaurant.