How did you plan for such an extensive trip and do you feel safe doing it in a power boat versus a sailboat? Is a power boat not more dangerous with the seas?

Firstly we have a trawler style boat. It is a displacement hull and very seaworthy.

True or False: Sailboats rely primarily on their sails. They are not worried about fuel needs and engine maintenance and are happy in a wide range of sea conditions. Bull S-----t! Wrong answer. Not true at all. It has been our experience that except for ocean crossings, sailboats motor or motor-sail most of the time. About 75-90 percent of the time. Also the range of sea conditions that sail boaters find pleasing is even more constrained than for trawlers. I'm not a sailboat basher, most of our friends are sail boaters. What I do want to convey is that trawlers and trawler crews, both properly prepared, can safely and comfortably cruise almost anywhere in this hemisphere.

Extended cruising isn't for everyone, hands on maintenance and lots of preparation is needed. A 2 month trip in the BC waters does require preparation but 2 - 5 yrs takes on a whole different meaning. Close to home you can usually get by even with poor preparation. However, a long involved voyage to the corners of the Caribbean or beyond is quite a different animal and the happiest and successful cruiser has done their homework before leaving the home dock.
Where do you start? First have an idea of your planned cruising area. Know where your interests lie. Do you want to travel inland? What is the condition of your boat? Have an idea how much you want to spend. We have spent more than originally planned but have no regrets. What is your experience level? Take as many courses as possible prior to departure. Some people learn as they go but I don't recommend it personally.
For most of the places you might like to visit, cruising guides are available. They are invaluable as an aid in answering many or your questions as well as providing information about weather, sea conditions, safe anchorages etc. We like to carry the inland guides to attractions and accommodations as well. We started collecting guides and started to build a knowledge base.
For this type of trip we believe a SSB radio with a weatherfax is a necessity. It allows you to keep in contact with other boaters keeping yourself safe. There are many boater nets that help keep track of the whereabouts of boaters underway. Internet has a great source of information. Now you can google earth the anchorages you want to visit and have an accurate map to use alongside your charts.
You must have a good GPS and backup, a good supply of spare parts, tools, food stocks, a good dingy and motor, a clear understanding of your boat systems and an extensive maintenance checklist. Keeping track of your maintenance will help you throughout the journey. Ken keeps an extensive log book that he refers back to constantly. We have pretty much double of everything to ensure that we are covered should something malfunction.
Extended cruising is no place for someone who depends upon others to maintain their boat. Boat problems rarely involve significant engine or transmission failures and I'm not suggesting that you need to be a engine mechanic, but a reasonably good understanding of the care of your boat systems will help keep your peace of mind. You should be able to think outside the box. Often you must engineer a part from the things you have on the boat.
A cruising boat is a tiny town. You will find that there are many systems, hydraulic, sanitation, water, fuel, communications, electrical, etc. Rarely can an individual be competent in all these areas, but it is key to have some understanding and to have adequate documentation aboard to help guide you through repairs. Nigels book helps a lot and should be found on all boats.
We planned for many years and have learnt a lot however we are continually reading, and listening to fellow boaters as they are a wealth of information.
I hope this answered the question without being too long winded.