Depends on the villas you book and from where you're going to be travelling from. approx 10 k if you're splitting among 4 people.
and traveling from Mumbai.
If you have your own car and and travelling from Mumbai then it's around 83 km and hardly will take 3 hrs max or you can opt for train's from Mumbai as lonavala has its own railway station. 2 night 3 day's are enough for you in lonavala and cna cover below location
Lonavla lake /bushi damn/lions point/ shooting view point/ dukes nose rappling/Khandala / lonavla wax museum/ Della adventure park along with travelling and accomodation wil cost you around 7-8k for 4 day's per head.
i will suggest you to visit between August-october
I also visited lonavala with my four friends on this feb. You have to keep budget of at least 8k per person.The place is very beautiful ,only thing is travelling within the city is little bit costly as there is no ola and uber services available. You have to go for local vehicles and drivers.
I hope this will help you.
Thanks.