Why not combine your stay at the Cottage with a couple of nights trekking (camping or local Lodge).

Availability will depend on the season.

Below is a sample itinerary:

Day 01: Drive to Kakani (2 hours). Trek to to Shivapuri Cottage (6-7 hours).
Day 02: At leisure at SHC.
Day 03: Trek to Chisapani (6-7 hours)
Day 04: Trek to Nagarkot (4 hours) and drive to Kathmandu or overnight in a hotel.

Note the above can be modified to suit your requirements.