Good job! I think you're going to like the simplicity of the MEP-003a you purchased it's a tough dependable machine if you take care of it & keep it out of harm's way... namely rodents & exposed weathering. My advice is to buy good fuel and be sure to treat it & your diesel fuel should hopefully be good for a couple of years plus depending on some fuel turnover. I use Optilube XPD & BioBore JF (kills the critters).
Run it with a substantial load for minimum of 15 min to 1hr monthly or no less than every 90 days. Consider stocking up on maintenance items like filters (fuel pump, fuel filters for cannisters, oil filters, air filter). Though you may want to consider the convenience of buying the adaptors for spin-on fuel filters and oil filter now before stocking up on the OEM filters.
You may also want to start making a list of spares to buy such as: a spare fuel pump, fuses, frequency transducer, glow plugs, the list goes on... It all depends on how you feel about being prepared for power outages & the frequency they occur in your area. Be forewarned that it can become an obsession... some people go so far as to buy spare engines, control boxes end even complete "parts machines" since these machines haven't been in production for 20 years and parts are getting scarce. It all depends on your dependency on electricity & your tolerance of outage durations & paranoia about it.
When power goes out here, I'm pretty screwed due to living in the country. I have two electrical service entrances 700' apart & dependent on keeping 2 wells running, 2 pumped sewage systems going, plus 4 horses alive & most importantly keeping the wife happy!