advice on quality of build, 1986 Viking 48' convertible

Look at the size of that cockpit. WOW. Near dance floor size.
Never rigged for salt water fishing (out-riggers). Big plus.
Please, please survey the motors very well and keep you foot off the throttles if you purchase.
Anchor, chain and windlass look wimpy.

Get the meanest surveyors you can find.

What is a "mean" surveyor going to do for you? I would suggest a qualified competent and accredited surveyor who will exercise fair and reasonable judgement.
What I mean by this is I've seen "mean" surveyors go completely overboard and basically beat the living daylights out of a boat. The buyer gets scared off from a boat that actually had no more than the usual survey deficiencies and nobody is happy.
I've also seen where the buyer thinks he's going to use a loaded up survey to beat the seller down on price. He buys the boat, turns the survey over to the insurance company, and now guess what? He's got to cure all 145 deficiencies in order to maintain coverage even though 100 of them should have been categorized simply under notes & observations. So be careful what you wish for.

Guys
You know me and you exactly what I meant. Making up bad waves is not doing anybody any good.
Leave the OP alone and beat up me if you don't like my verbiage.

When you purchase any thing mechanical, especially if your away, you want to know everything. No pussy lil survey, I would want to know every bad hose and bad hose clamp on that boat. Every rusty screw on that boat. Every bad crimp on that boat. Where every rust stain came from. Every bad window gasket. Every lay of caulk that looks poor.
Yes, I want a POd surveyor. Pull out that thermal gun. Pull out that IR camera on the hull, batteries and wires. Snake cameras are used today. Bring them on...
Put that IR camera to use on the power wires to the VHF radio when TXing. Also on the radar.
I want some heavy guy or two swinging on the arch, mast or gin pole. I want to see that windlass pay out and pick up a couple of yard guys. How far did that pulpit bend down?
When you have a whole truth of it's condition, the best picture you can get, on paper, in front of you,,then the OP can evaluate if the boat is worth his money.

exercise fair and reasonable judgement

Where is the start / stop line on this. Written in the bilge some ware just before that bad & hidden bilge pump crimp is hiding?
Again for me, I would want the most complete non-destructive survey and inspection I can get in two days. Not only is my money at risk, lives could be threatened.

Deal or not, the safety of the OP and his family may reside on a real deep survey.

Nuf said or do I need to type slower?

Anybody that has anything to swing also knows there are two surveys, one for the purchase and one for the insurance company.

Oh, The same goes on the engines.

Have a nice day

Jack Morman surveyed a boat I ended up buying. I thought he was first rate.