To add to the point above: I know you are in a rush, but dont let the fear of high mileage totally scare you off. These trucks are famous for hitting 300k miles if they were actually cared for. Since you only have until Sunday, here is how I would handle the search to stay safe:

• Look for the 4-cylinder models. Most people in Denver obsess over the V6 for mountain driving, but for a landscaping gig around town, a Toyota Tacoma 2012 2.7L 4-Cylinder is plenty. They are usually cheaper and easier to find with lower miles in your budget.
• Ask the seller for the VIN and run a Carfax immediately. If they hesitate or make excuses, just move on to the next one.
• Hire a mobile mechanic for a Pre-Purchase Inspection. Since you dont know much about cars, this is the best $150 you will ever spend. They can meet you at the truck and check the engine and transmission for you.
• Look for a Toyota Tacoma 2013 Access Cab 2WD if you dont strictly need 4WD. Taking the 4WD requirement off the table drops the price by thousands in Colorado. Ngl, $17k is a decent chunk of change, but it goes fast here. If you see a Toyota Tacoma 2011 Base Regular Cab with 140k miles and a clean frame, thats actually a solid bet. Just check the oil dipstick... if it looks like milky coffee, run away.

To add to the point above: I have been around the block with these trucks in the Denver area for a long time, and you really have to watch out for the "Tacoma Tax" around here. Everyone wants one for the mountains, so prices are inflated. Since you are stressed about the mileage, keep in mind that a Toyota Tacoma 2011-2015 V6 4WD is usually just getting started at 150k miles. The 4.0L engine is basically bulletproof as long as the previous owner actually changed the oil. Since you need this by Monday, maybe skip the big dealerships and check out some independent lots or even reach out to local Toyota enthusiast groups. If you can't find a clean Taco in your budget, I’d honestly look at a Nissan Frontier 2015-2019 SV V6. They aren't as flashy but they are solid workhorses for landscaping and you can find them with lower miles for $17,000. Before you buy anything, try to check these things:

• crawl underneath with a flashlight to look for scaly frame rust
• check the Carfax for regular maintenance intervals
• make sure the 4WD engages and disengages smoothly Ngl, buying a truck in three days is a tall order, but don't let the pressure make you skip a pre-purchase inspection. Any decent seller will let you take it to a mechanic for an hour. Good luck with the new gig!

Try searching on Facebook Marketplace or Craigslist. In my experience, dealers in Denver mark up Tacomas way too much. Over the years, I've stuck with the Toyota Tacoma 2005-2015 2nd Gen 4WD because they're easier to find in your price range. Just crawl under it and check for frame rust first. I can help you look at listings if you want.