Please do not buy a portable generator-- those things are now the scourge of both Avalon and Isthmus Cove, even beyond. (Sorry Rick D!) I suppose I'm among the few who do not like to be surrounded by 'em. Some experts here may offer you other reasons not to get one from a safety perspective. Not that I'm unsympathetic to your power issues; I've been working on my own for several years now. I did buy a portable generator for one long trip; however, I took it off of the boat shortly afterward and sold it this year at a boater's swap meet. They are not the solution IMHO.
In my opinion--the solution is a combination of decreased power requirement, solar combined w/ diesel engine charging, and strong, well-maintained, batteries. Make sure the fridge is insulated well at the door--e.g. replace the seal w/ a new one. Turn it up (warmer) to maintain 40 to 50 deg temp cycle. If you have radar keep it on stand-by unless using it to range, or off when sailing. Do not sail much using the autohelm; use mostly only when motoring. If motoring to destination turn it off in the final hour b/f entering the anchorage and steer manually. Use a lantern below at night with LEDs or fluorescent lights. ALWAYS TURN OFF EVERYTHING that consumes power that is not being used, even the propane solenoid valve, etc., and the stereo. Turn off cell phones except to make a call so you do not have to keep recharging them, etc. Do not use appliances that require a large inverter. I think you get the picture!
Get a couple of solar panels of at least 85 watts, maybe larger ones or more of 'em, plus a battery charge controller/monitor. Charge all day, then "top off" with the diesel for an hour before turning in. Charge at 1200 to 1500 rpm. Make sure your charging alternator is working as it should. Get new, true deep-cycle, house batteries if yours are more than 5 years old and learn how to take care of 'em!!
PS--I hardly ever see or hear portable generators at the northern Channel Islands and many people, including me, anchor out there for 12 to 14 days at a time, or longer. Yes, the batteries still go down some after a couple of weeks. But, it works well enough for those relatively short coastal trips away a from AC power. It's a different "culture"; we love the pristine--sight and sound!!