?? I don't see any quests that are 'scout or research'. I see 'scout or upgrade' but all you need are a couple of 2 * 1 slots in your city. Build 2 T1s - heck, splurge if you can and build 4. Move them up right away to level 4; that only takes about an hour total. Then you are ready to move them quickly up to level 5. IIrc for Elves, marble and planks only take half an hour to go from 4 to 5; humans have it harder with marble being the smallest footprint but taking an hour and a half. That still doesn't mean burning a ton of time instants.
Once they're at level 5 & you get credit for the quest, sell them & repeat the process so you are ready to go the next time the level-up option comes along.
The quests that require research have an option of CCs or VVs. Both should be more easily do-able for a Ch 19 city, right?