Alaskan Cruise Coming Up - advice sought

[MicheleF]

We are leaving from San Francisco next week for a 12 day cruise to Alaska which will include the inside passage as well as ocean sailing.

As a newbie photographer, I am seeking advice on two things.

WEATHER:
The forecast includes lots of rain and clouds.

I plan to put my camera around my neck (I use a black rapid strap), do I need a raincoat for my camera?

I plan to leave the ship with my Canon 15-85 F3.5-5.6_ IS USM lens on the camera. Should I bother to go off-ship with my 50mm 1.8 fixed and/or a Canon 75-300 F4.-5.6 ? Or should one of those be on-camera for most shops and I should carry the others? Or go out with just one lens?

Any advice on settings for shooting in overcast or misty conditions?

BORROWED LENS
I'm lucky enough to work in the corporate office of an independent photo retailer (which is why and how I decided to take up photography). Sigma has loaned me a Sigma OS 150-500 F5-6.3 lens. My plan is to use it only on the ship, for landscape or wildlife shots, and not carry it around - it weighs 12 pounds. If there is anyone who has cruised Alaska, I'd appreciate some advice as to whether this is a good plan or do I bother to bring it at all?

They also sent over a Sigma OS 17-70 F2.8-4.0... Would you recommend I bring that over the Canon 15-85?

I have circular polarizers for all my lens - is there anything else that is a MUST or a NICE to have? I have access to just about anything I want if it's in the store.

It's my one shot at Alaska - I wish I had been studying photography a little longer!

Always appreciate the feedback,
Michele

I've also

[OsmosisStudios]

I'd suggest the 15-85, but I'd definitely be tempted to bring the 150-500 with you, as big as it is. Alaska is BIG. Really big. Surprisingly big. There are situations in which you'll feel like the 500mm is a HUGE plus, and warranted.

The 15-85 will likely be used at the 15mm end for landscapes.