Sounds like you have a good plan. Harbor Freight tools has a pretty cheap borescope at around $79. If you happen to have an Android phone, you can get one for $10-$15 on eBay. iPhone is a little more hassle / more expensive. It probably won't show you much though, and it definitely won't help you do anything about what you do see, so if you happen to know someone who has one great but I wouldn't spend a ton of cash on it just for this purpose. It's a good tool to have for a professional mechanic or a hard-core home mechanic, but not a must-have.
You can theoretically get the pan out with engine in, but it's really really tight, and you have to blindly undo the pump and pickup to do it, and to get them back in. It's also a huge mess and hard not to damage the gaskets going back in, and I'm just getting too old for that kind of stuff.
I've found over years of toughing it out that it saves me time to make some room before I start. Of course that's a ton of work too and requires a hoist. I'm confident you'll get it done however you go about it.
As we've mentioned before, most likely you've got some engine wear, and this will be a 'temporary' fix, so picking your temporary fixes in order of ease and expense is the way to go. Flush, heavier oil, followed by high-volume pump and pickup screen replacement, followed by a rebuild. I've gotten an extra few years and tens of thousands of miles on an old engine by installing a high volume pump, so that's better than a band-aid in my book, especially if you're not burning oil and have pretty good compression. The 'right' way is to rebuild, but that's expensive and the car may or may not be worth it to you, and getting it to run good enough can buy some time. By the time it needs to be rebuilt, a lot can happen so I never look down on 'temporary' fixes. Cars are all temporary.