Something you might consider getting into is the limited energy/communication side of electrical work. I started out doing hotels/motels, and the work is very easy, all things considered. It's also easy to bankroll extra stock for jobs; if you need 21,000' of coax, it will probably come out cheaper to buy 25 rolls, which is usually a price point break. If you can, try to upsell the owner on going with conduit to future proof the building. Again, if you need 8,500' of ENT, and 400 3/4" fittings, it'll probably be cheaper to buy 10 spools and 500 pieces.
Commercial v/d/v work of that nature sounds like you'd need a big bankroll and crew, but, with few exceptions, every hotel we did from 65-145 rooms was a 2 man job.
Price shop materials as much as possible. The above mentioned fittings can vary almost 25c each, or $125 total. Little things like wire nuts, Wagos, NM fittings, boxes,and so on can vary in price a lot as well
I've found 3M/Hilti firestop that sells for $15+ a tube at a bb store/supply house for $2 on ebay. Expensive tools like roto-hammers and bits can be found cheap there too.
One of the things I used to watch my previous employer struggle with was keeping enough of 'trivial' materials on hand/in the truck to complete a job w/o going to the supply house. That the nearest one to you is 70 miles away means you absolutely cannot afford to run out of silly things like blank cover plates, cut-in boxes, switches, receptacles, etc. You may have to do some more planning/digging for small jobs; say you get a call to add 3 receptacles for a HO. Make sure you ask them things like 'what color are your devices?', 'what style?', dont assume all white, and standard, lest you get out there and find they have light almond Decora and your stock doesnt match. and always buy at least one more than you need, that way when the HO says "oh, while you are here, could you add another receptacle in the garage?", you have it covered.
In two words: be efficient.
Organize your work vehicle like crazy. I learned this very quickly as doing commercial work, my truck might be up to 600' from the building. If I had to send my helper for materials, I needed to know exactly where to tell him to look, and at the end of the day, everything had to go back in its place as space was at a premium.
Back to v/d/v for a moment, the tools are a bit expensive, and many electricians do not mess with it. If a HO calls for a recessed receptacle for a wall mount TV, you should be able to upsell moving the CATV to be hidden as well, and have the tools/know-how to do it. Please do not construe my post as condescending to a master electrician (gratz btw!); just in my experience many are not proficient or lack the proper tools to do that particular work.
It also helps to have stock to show the customer for upselling. Keep a few LED trims on you; if you see a customer with can lights and CFL or incandescent floods, pop one in to show them the new technology. Explain how they save money on power, and last a long time. Books or flyers or a tablet (internet) that show the product are helpful as well, especially for things like floor outlets that are expensive, vary greatly in styles, and may not move that much.
On the subject of van vs truck, Id take my 1994 extended cab 8' bed w/camper shell GMC truck over a Sprinter any day. I put eye bolts right thru the shell to hold ladders (so no expensive ladder racks, better clearance, and you dont need a ladder to get to the ladders), and built simple custom boxes inside to hold materials efficiently.
"For me unorganization is a killer and a consumer of profit. Getting a service call and having to make multiple trips rather than one.."
Brainstorming for 10 minutes over every possible thing you may need will alleviate a lot of those trips. Do not think of this as unproductive time; as the saying goes, "An ounce of prevention is worth a pound of cure".
Finally, it is tempting when you have a low budget to buy cheaply made materials and tools. Dont. I have seen cheap cat5e cable with counterfeit UL markings, and tools to terminate the cheap, crappy keystones of the same fall apart quickly or take 3x as long to use as good ones. I dont think this is as much a problem on the 'electrical' side vs communications, just beware there is some absolute garbage out there.
Good luck and I hope some of this post was helpful for you.
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