On top of nandi hills, there are rooms available. They are perfectly safe except for scorpions and such. I mean not excessively but still one needs to be careful. I have been there many times in the past.
On kanakpura side there are many farms. If you are looking for suggestions, you can send me an email.
And on bethmangla side there is another farm house. You need to book in advance and this place can accommodate large groups. Ultra safe and an urban farm. But suffers from a bit of stray lights at the horizon. But that is made up by the fact it has good toilets, high walls/electrified fencing be and at a less than two hour drive from KR puram.
Also, lot of BAS members go to some farm in koratagere. I have not been there so can't comment but someone on the list can help you with that.
Of course, am assuming u want something at a short distance from the city.