I had an old King autopilot on my 1986 Grady with manual steering and a Raymarine S1000 on my current boat with hydraulic steering. For long runs over the horizon, nothing beats an autopilot. Instead of being beat up from fighting the helm after a 2 hr run, I'm ready to fish.
The main reason I got an autopilot was to save fuel. I'm a terrible helmsman without visible landmarks, even when following a Loran/GPS track. It's impossible to steer as straight as an autopilot. I found that an AP saves me at least 20% on fuel consumption. When my S1000 gave up the ghost on me last summer, 30 gallon trips become 40 gallon trips. And I was happy to let the other guys fish for the first half hour after arrival while my 72 year old body recovered. We lost fishing time as well since it took longer to get to waypoints.
There are 2 things to consider before spending the money for an AP. The first is the distances you will be running and the second is the sea conditions. From your posts, it appears that you (trapper) are on Vancouver Island. If you are running on the inside, an AP should be helpful if you generally run long distances. The sea conditions should be fine except for tide rips. The Pacific can be another matter depending on the swell height and wind waves. You will find that running on the AP can get you wet and beat the crap out of you if things are sloppy. When you are at the helm yourself, you are constantly making little adjustments that minimize the effect of the waves. You may not be aware of this until you run with an AP. I find that in the Gulf of Mexico I can usually run on AP with up to 2 ft of short chop. Anything over this and I grab the helm myself.
As we discussed in other threads, I'm putting in a Furuno Navpilot 300 to replace the old Raymarine. For my purposes it makes sense. I've used an AP for trolling down here with good results. But when I lived on Vancouver Island I mostly trolled tide rips and offshore structure. I needed to be at the helm to do that effectively. So it all depends on how you will use your boat.
As far as installation goes, I put the S1000 in myself. The only hard part was hooking up the pump to the hydraulic steering. That required figuring out where to put the pump, changing some of the connectors that came with the unit, and bleeding the system. That was a sloppy mess. I was going to have the Furuno put in professionally since I'm now old and pathetic, but the quote I got was ridiculous. They wanted to bill for 10 hr of labor despite the fact that the already installed pump is going to be used. So I'll be putting this one in myself pretty soon. I haven't done any NMEA 2000 stuff yet, but I guess it's time to learn.