bus from Kampala to Fort Portal

Sorry, meant to say I was planning to take the Post Bus...

I tried to take the post bus with no success. I think all the companies are the same. You don't need to book in advance. I envy you being in Uganda:)

When I travelled with the Post Bus, I bought the ticket the day before travelling.
I was coming from Kabale, not Kampala, but it wouldn't hurt to try if you can go to the depot on the Wednesday. It's just behind the main PO.
Our bus left about half an hour earlier than I'd been told when I bought the ticket, so it would be best to get there early whether or not you buy your ticket the day before.
(Their website says the bus for Fort Portal - Kasese route - leaves at 7.30am anyway. I think I'd try to be there at 7am to be sure).

The Link buses leave from the small bus park near the old taxi park, they seem to just leave when full, so if you miss the Post bus you don't need to worry.

Kalita was the name of the company I used I remember now. Quite nice, full of live chicken though:) When I tried to use the post bus someone told me they don't cover this route anymore, but reading the other comments here I think they were wrong.

Strongly recommend getting ticket day before and heed other advice, as sound. Once out of Kampala, route is very smooth. No roadworks, unlike route to kabale.