Taxis are abundantly available in Cameron Highlands in both the Tanah Rata and Brinchang towns. Taxis usually charge 25 to 30 MYR per hour.
If you eventually decide to book a tour, don't book one online. There are plenty of tour operators available in both Tanah Rata and Brinchang and you can explore them and select a package that better suits your personal preferences. In my personal experience, the Tanah Rata Tourist Information Center from where they sell the bus tickets offers good quality packages, their tours are well organized and their guides are better. This place is very close to the Planters Hotel (Just to give you a landmark).
It might be a good idea to hire a taxi instead of a tour since having your own transport gives you the flexibility to decide where you want to spend more time and where you want to move quickly from.
Cameron Highlands is an easy place to navigate since there is just one main road on which all the attrations lie. However, make sure that you don't go there on a Saturday or Sunday since the road after Brinchang (assuming that you are coming from Tanah Rata) is usually jammed because of traffic, so it becomes prohibitively time-taking to visit the Market Square or the EQ Strawberry Farm, the BOH Tea plantation etc.
However, the Brinchang Night Market, that in my opinoin is definitely worth a visit , opens only on Friday and Saturay nights.