$150k doesn't leave much wiggle room for even a piston single if you are thinking about Western US to Island flying. It's not just the initial buy in, but it's also the ongoing maintenance. You can consider a vintage Cessna 310 or Piper Seneca as well, but before scratching the check, make sure you talk to twin piston owners and A&Ps about the direct operating costs and yearly maintenance so you don't go into it with a huge grin, and then a year down the road an ugly scowl when you're staring at an major repair/annual bill.
People new to aviation tend to buy at the very top of their budget range, which is a quick way to find oneself drowning in financial liabilities. There is a school of thought that a twin piston just "gets you to the crash site faster", and that you are doubling your chances of an engine failure, which is not unfounded.
Just make sure you've done all your research before you buy. You might find a single engine Mooney or Cessna 210 acceptable for 90% of the flying you want to do.