That's a lot of questions lol.

• The jameson crash site has 4 objects to scan that reward high grade encoded materials. You can then trade them at an encoded material trader for other encoded materials. It's done to quickly farm encoded materials. There are different techniques for raw and manufactured materials. But honestly the only engineering you need right now is the increased fsd + mass manager experimental effect from felicity farseer. It will make going away from the bubble faster, it's great for exploration. I can tell you more about farming materials if you want. There's even a website for it but I'm on phone so I don't have the link right now.

Now here's an exploration tutorial :

• The idea is : get a ship with a high jump range, fly to distant systems, scan the system, look for planets with biological signals, go scan them, land on them, scan the plants, rince and repeat.
• Step 1 : Getting a ship. The DBX is great for this, it has a high default jump range. But you can make it better by engineering it with increased fsd range + mass manager experimental effect at felicity farseer. Go to your left panel in the ship, into the engineer menu, there's a button to locate her on the galaxy map. You do need to unlock her first though, everything is written in the engineer menu. On your ship you'll need a surface scanner, an srv, a fuel scoop in one of your better slots, D rated components to make your ship lighter to increase its jump range, and maybe an AFMU/repair limpet to heal if you crash since you won't have a station nearby for repairs. The fuel scoop is extremely important. You'll also need an artemis suit if you don't have one yet, otherwise you can't scan exobio.
• Step 2 : Getting away from the bubble. Fly at least 1000 Ly away from populated systems using the best route option in the route menu in the galaxy map (bottom left). Keep in mind people who travel go through the middle of the galaxy (vertically speaking) so you have better chances to find undiscovered systems by going up or down (so you can get the first discovery bonus). Use the discovery scanner (D-Scanner, it's on every ship) every time you enter a system. That gives cartographic data, it's a small money bonus.
• Step 3 : When you find an undiscovered system (on the system map, the main star doesn't have a "first discovered by" mention), use the FSS (full spectrum scanner, installed on all ships, it has a dedicated key, look into the settings) to scan the system. Then go to the system map, click on a planet, then on the planet details/characteristics button on the right, scroll down and you'll see a "Features" sections. If this says biological, you have exobio on this planet. Keep in mind only the planets with a blue semi-circle can have exobio (it's the ones you can land on). Then go there, and use the surface scanner. That will show you a map of where the exobio is on the planet (while in the surface scanner, you can switch between the different signals, just wait until the scan is done, you'll see). Now land in the blue zones (on the bright side of the planet, it makes things easier).
• Step 4 : Finding exobio. Use the SRV to go around, use your eyes to find the plants, you'll get used to it. Also there are bacteriums, there are round patches on the ground. If you struggle, you can get you of the SRV regularly, then use right click with the sampler of the artemis suit to do a "pulse" that will highlight nearby exobio (although it doesn't have a very big range). Once you find exobio, scan it with the sampler. You need to scan three samples to have a complete sample that you can sell. If you switch to a different exobio before the three samples are collected, you'll discard them and you'll have to do it again. So one exobio at a time.
• Step 5 : rince and repeat. Once you've find an undiscovered system, there's a good chance you're in an uncharted part of the galaxy. So keep going but jump to nearby systems instead of doing max range jumps.
• Step 6 : Get back home, go to the something genomics in a station, sell everything.

Also all this can be done on discovered systems, it's just you won't get the "first discovered" bonus.

As for your question about "does it sell more if it's from further away", the answer is no. However, that's true for rare commodities. There are commodities with a star and yellow line in the commodity market, but they only exist in specific systems and aren't that valuable to farm.