Going to Sweden - need a little help

[golden]

I will be in Sweden from 9 to 13 October,doing some medical training. I will be busy most of the time but want to do my best and visit as many interesting museums/parks/nurseries as possible.
I will be free on Friday morning (till 12am) and the whole Sunday.
I was thinking of doing some boat sightseeing on Friday morning.As far as I can understand most of the boat trips are NOT available in October...probably the Royal Canal Tour is still available-do you have more information about this?
I plan to visit on Sunday the Skansen outdoor museum and the Aquaria watermuseum. Are they near to one another?
I didn`t have any success in finding information about orchid nurseries in/near Stockholm.Do you know any?

I will be staying in the Adlon Hotell, Vasagatan 42, 111 20 Stockholm. Any interesting museums or parks,botanic gardens in the region?
Any info and practical advises will be of great help