Our shortest time on shore, but we knew what we wanted to do and had plenty of time to do it. Took the shuttle bus into town $7 to save time walking in. It was about a mile, but would have used up valuable time, so the bus seemed a good idea.
Took the cable car up to Monte. It costs 10 euro single and 15 euro return. We got single tickets and then made for the toboggan ride back down which was great fun! The toboggan costs 12.5 euros each and is well worth it. It is not at all dangerous and you should not be worried about sustaining any injuries.
There is also a very good botanical garden at Monte, but we didn't go there, although we could see down into it from the terrace at the top. Very nicely landscaped.
We got a taxi back down the latter part of the hill after getting out of the toboggan, again to save time. Taxis are everywhere.
The Old Town is very arty with lots of murals on doorways & walls & lots of interesting individual shops. Found an outdoor bar and sampled some Madeira wine AND brandy at lunch time. Very reasonably priced. We bought a bottle of Madeira to take home and it cost 7 Euros.
A very nice day out.