In this market you can get a pretty nice liveaboard trawler for 100k or less.
You have not said where you intend to keep the boat and what sort of crusing passages you are thinking of making. Based on your location I would guess somewhere in Puget Sound / Vancouver / Straits of Georgia which is a GREAT cruising area. You are not out on the open ocean and towing services are available SO in the event of engine failure help is at hand. In that situation I would be happy with a single diesel. You could add a mount for your tender OB say a 15 hp on your stern and that would push you along too if needed unless conditions were evil. But as a full time liveaboard you don't go out in evil conditions.
Yes twin diesels would make the business of manouvering in tight spaces easier but a bow thruster takes care of that too. Twin diesels will cost more to buy and to maintain but of course you do have the comfort of having that other engine if one fails.
A single diesel should be more economical than twins.
As it gets cold up there and you talk as if it is going to be a full time liveaboard then insulation and heating will be critical. I suspect you will want an enclosed aft deack with a sun deck above for the good days of summer.
Either of these would be worth a look
42' Doric Boat Works Pelaglic Trawler CLICKY
36' Gulfstar Trawler CLICKY