Is my Stockholm plan reasonable?

[MN'smom]

Our ship (August 17) will be docked in Frihamnen from 8:45-4:10. Is it reasonable to expect that using public transportation we could take Bus 76

to the Vasa Museum, after visiting there, take the ferry to Gamla Stan, explore some, go to the Noble Museum, then take Bus 76 back to the port? I'm concerned that this may be too ambitious a plan to do justice to each stop with the time allotted. We typically prefer doing fewer things really well then quick visits to many sites. We are fine with a quick snack rather than an actual lunch. 

[Desdichado62]

You should be able do what you want during the stipulated time more or less but It is totally dependent
on how much of Gamla Stan you want to see.

[MN'smom]

Thanks! 

[kitkat343]

If you get to Vasa first thing, it will hopefully still be empty,  so you'll be able to see it much more quickly.  It was dead empty when we got there at opening, and packed by the time we finished visiting.

[MN'smom]

That's my plan and hope also. I'm assuming we'll need to be back on board by 3:40. To be safe, what time to you think we should definitely leave Gamla Stan?