Looking at big boats, I once imagined owning a 50ft Maple Leaf that was for sale near my home. Nothing wrong with looking. Just be sure about the boat and it's needs before you let your imagination open your pocketbook.
1. I sailed a 15ft Montgomery for 18 years. We explored rivers, lakes, bays, the ocean a couple of times and the Puget Sound in the PacificNW. It was like camping in a one person back packing tent. Lots of fun. My dreams and more available time led me to sell the Montgomery and purchase my current 35ft Cal Cruiser. For the solo sailing, I enjoy, and the ability to carry family and friends a 35ft boat fits. The gear is not too difficult to safely manage. The cost of moorage and repairs are affordable. I would encourage you to spend a lot of time with your present boat. Small boats hone your sailing skills. Moving to a complex big boat can be less safe. You can quickly find your self spending more time fixing things than sailing.
2. It is not the boat but the sailor that lets you safely sail off shore. Explore the experiences of others, like the Pardey's (
Lin & Larry Pardey Sailing Stories & Cruising Tips) they crossed oceans in a 24ft boat Seraffyn.
Voyaged - 47,000 miles - eleven years, eastward through Mexico, Panama Canal, to Europe and Baltic. Three years in Mediterranean, south through Red Sea, across Indian Ocean and through China seas to Japan, then Canada and south back to launching port of Newport Beach, California.
3. Safe Sailing is, in my opinion, knowing the weather, knowing your boat, knowing your skills and then making good decisions. Your ability to make critical decisions comes from studying the knowledge of others and comparing it with your own experiences. Give yourself as many experiences as are possible, then grow boat size and sailing adventures.
Here is an interesting site.
Boats for sale - Global Solo Challenge