I would be tempted to book ahead so you can relax have a look at http://www.palmgroveresidencygoa.com On transport you could take a taxi but also a bus from Panjim to Margao and then the Margao to Mobor bus which passes through Benaulim, Cavelossim etc.

Here's how me n o/h did the journey from Anjuna to Cavelossim last December-

7.45am bus from anjuna to mapsa 7rps each
8.15am bus from mapsa to tivim 6 rps each
9.28am train from tivim to margao on Konkani Express 28rps each (we had around half hour to wait for the train at tivim but you can get refreshments on platform 1)
Arrived at margao station at 10.30.
10.40am bus from top of station road to margao centre municiple gardens, I think that was around 5rps each
When we got to Margao we got a rickshaw to Cavelossim but can't remember what we paid for that, wasn't much though.
We had pre-booked our acommodation at Gaffinos as we had friends who were staying there but we wouldn't have bothered otherwise.
I know a taxi is quicker but it was a great day and it was something a bit different for us to try as we'd used the buses and taxis before. Very enjoyable.

Good luck, whatever way you choose