You can try some of the DYI fixes. If they don't work, ask around, get recommendations, and find a nearby honest pro generator repair shop. Diagnosis and repair of your generator, may cost you some $800, maybe less if it's simple. Lot's cheaper and more convenient than buying and using a portable generator plus it will make your rig easier and worth more when you sell it.
When you get it running again, run generator with roof AC frequently and maintain house batteries and connections to help it start easily.