I think the amount of work and cost involved with an inboard will depend on what's currently in the boat. Are the thru hulls there? Prop shaft? Tank? Was it an A4 or a diesel? Are you willing to do some work yourself?
I've seen an Atomic 4 or 2 for pretty cheap, but if you are going through the expense of having that installed, might as well get a used diesel while you are at it. The more you do yourself, the more you'll save, paying $60/hr+ for someone to run a few tubes and install a tank isn't worth it if you can manage it yourself (OTOH it is for things like alignment).
Feasibly you could probably use an outboard and get away with it, James Baldwin outfitted an Alberg 35 with an outboard well:
Atom Voyages - Saga - Alberg 35 Refit Projects
Comfort and ease of use, especially without a well, is a different story though. I'd expect you would arrive at your destination, but not comfortably and not as efficiently as you'd like.
I think you'd do fine if you had the ability to sail and use the outboard, but if you can't sail the boat and are planning on using the outboard the entire way, I'd try to figure out how to get an inboard in or fix the mast problem.