This is as good an area as any if Long Barrows are your thing... Cold Kitchen Hill and Pertwood Down nearby. Wiltshire has many others, Fairmile Down, Tilshead Old Ditch and Lanhill amongst them

Hillforts..... my favourite in Wiltshire is probably Yarnbury - although note the land owner - with Scratchbury and Battlesbury a great pair.

Not sure if you've been before, but you could spend a week around Avebury itself... and if you could arrange an 'out of hours' at Stonehenge... I would.