The Bear's cautious two cents worth:
First: Almost very boat that you would find acceptable is the six figure range or (gasp) and the first numbert isn"t a 1!
Three: There are three TRAILERABLE boats that have hundreds of times proven themselves very "blue water worthy" Pacific Seacraft's "Flicia" and "dana" and Nor'Seas 27. These craft have made hundreds of tran Atlantic and Trans Pacific and circumnavagations, safely, comfortabley, and are relatively inexpensive. Any one of thse boats can be found, used, in the mid five figure range.
Four: These are boats that "we" can afford and I submit add these production boats to your list.
Sorry for editing your post but I wanted to focus on a couple of things you said
based on our experience in the Eastern Caribbean and South Pacific.
First of all, the boats you see actually cruising thousands of miles from home vary enormously. In fact, we have seen probably 200 different designs (haven't counted). There is no best way to go - it depends on the individual's (or couple's) predilections and budget.
The median boat (half cheaper/half more expensive) we saw in the Pacific (a very long way from people's homes in North America, Europe, or Oz could probably be had for something like $120,000. In the Eastern Caribbean, probably the figure would be less than 100k. But we saw people having a great old time in Vegas (is that 27?) and we saw one guy with a Bristol 27 in Suwarrow and Pago Pago. His Monitor vane and solar panel were probably worth more than the rest of the boat. You don't need 'mid 5 figures' for boats like these, much less in today's market. (BTW, I don't think these boats have made hundreds of transoceanic passages and circumnavs - but they have made them)
What you get in a bigger pricier boat is not necessarily more safety - it is more comfort and faster passages. If you want to cruise you can do it safely and cheaply. If you want more comfort and speed, the sky is limit up to the mega yachts we saw in St Martin and Tahiti. In the latter category there was a gorgeous 104' (looked like a classic but was quite new) that looked almost tiny next to a couple of other sailboats that were more like 160'. You pay what you can and live with the consequences, but you can be cruising long distances. I was happy cruising on my Niagara 35, but the admiral said she wanted something more comfy if we were heading off - so we got the Bristol and have enjoyed the comfort and speed.
A comment on what a few said about conditions way offshore compared to near shore. They are not the same even if you can get some lousy weather near shore. When you a thousand miles from nowhere, the consequences of something breaking are much worse as are the consequences of illness or accident. There is no Boat US or even Coast Guard to help you.
When we were going from the Galapagos there was a woman singlehanding on an old 37' ketch. She had her forestay break and later the shaft flexible coupling break. The mast stayed up because of a baby-stay but she had to jury-rig and find some way to get to windward a bit because the winds were not the standard trades and she could not lay Easter Island. With the conditions as they the next harbor was Mangareva in the Gambier Islands which was close to 2000 miles downwind. We, along with a three other boats, were in an informal SSB net with her and were able to contact the Chilean navy. They said they could rescue her but could do nothing for her boat (eventually they towed her the last several miles to Easter). When this started we were 600 miles away from her but upwind so went toward her in case she had to abandon. The boat coming behind us (200 miles) took her some water since she was running out and did not have a water maker, nor did it rain much. The wind switched and she was able to get to Easter. For two weeks she probably averaged 2 knots but she made it - a hell of a good effort on her part. That sort of thing happens offshore but not near shore.