Kampot is a small town on River, near the ocean. You can walk around most of the town in one day.
However, outside of town, there're many great sights, big and small, that you need transportation to get there.
The biggest experience is a tour up Bokor Mountain. You can rent your own motorcycle for $5 a day and go up, or there're about 10 places giving tours where you ride in a van or the back of a pickup truck.
Also, around Kampot are waterfalls, salt fields, pepper plantations, Wats (Buddhist Temples), caves, and beautiful mountain and countryside scenery.
The Kampot River itself is also a destination for boat tours, fishing, and other activities....
All guesthouses in Kampot can arrange tours to any of these places. Some companies in Kampot specialize only in tour services.
Buggies, or off road vehicles have become very popular here recently. Might be $40 for a half day, and some places have tours.
You can also rent bicycles, tuk tuks (a cart pulled by a motorcycle), motorcycles and cars with a driver / tour guide. Bicycles rent for $1 or $2 a day, and motorcycles (small ones, most are automatic with no gears to switch) are $4 - $6 a day. Big dirt bikes are $10 and up per day.