My top 3 are all nearly equal in their own right.
In no particular order....
Currently 31 years old, about 3 years ago my wife and I bought 1 way tickets to Asia with absolutely no plans aside from our first week booked in a hotel in Bangkok. I had just finished 4 months of (7) 12 hour shifts/day with every other Sunday off. Prior to that I’d been working 60-70 hrs a week the past 6-7 years with no more than two weeks off per year. I have always been very OCD about my work, structure, and schedules. I was 50/50 that we’d end up back in the U.S. in a week and I’d be ready to go back to work. After the shock wore off, I realized that I could actually RELAX. We spent two weeks in Bangkok, 2 weeks in Phuket (got certified to scuba dive for 3 days off Phi Phi island), then a week in Cambodia, Laos, Vietnam, and Singapore.
As that trips was winding down, I had been building up a dual sport/touring motorcycle to do a major trip. Being February we were limited. So - when we got back we planned a 3.5 week, 3000 mile trip through Baja. We camped on the beach under the stars every night. When we got to Cabo we used 3 days of credit card rewards to pay for a few relaxing nights at the Hilton before our trip back. We were up close whale watching as 3 gray whales came right up to our little john boat that we could touch. They stayed and played for over an hour. We took off-road paths and went down in the sand, crossed streams, met lots of Canadians who came down to camp the beaches for the winter.
We went back to work for 4 months, then got unexpectedly laid off. We immediately picked up a 1966 M416 off-road camping trailer with a roof top tent to pull behind our 4Runner. We also had a 12 week old German shepherd. We did over 8000 miles in two months, camping in the tent every night but 3. Went up through Michigan, their state parks, Mackinac island, northern peninsula, over to WI, then to the badlands/black hills. Up to Banff/Jasper for 3 weeks, down to Yellowstone (got snowed on in the tent) to the Tetons, taking the Continental Divide trail down through Colorado in late October with the changing leaves. Hopped off over to Ouray for several days, down to the Grand Canyon, then finished visiting family for a couple weeks in AZ until I found the next job.
We would easily do any of those trips again in a heart beat. When I finish my current contract position (which will be mid 2021 at the earliest) we will be doing another major camping trip, or at least that’s the plan. We have bought and have been extensively preparing a 17’ casita trailer, adding a 4” lift, off road tires, generator, etc. We’re taking it on a two week trip over Christmas, it’s making it really hard to finish out this job, but each month I work I save enough for nearly 3 months of sabbatical... must... keep... going....