Reddit mentions of Rode PG2 Pistol Grip ShockMount for Shotgun Mics

Considering you have $300 to spend you can do a bit to improve it. First I'd recommend getting a hyper cardioid mic for recording indoor dialogue, much more suited than a shotgun. Something like a Oktava MK-012. Next you'll need a boompole so you can get the mic close to your actors, this should suffice Rode Micro Boompole, doesn't need to be to big because you'll be indoors. Lastly you'll need something to attach the mic to the boompole, this works perfectly Rode Pistol Grip. Now I realise this is a bit over $300 but its not that much more expensive and it should help your dialogue quite a bit. Try and shop around a bit if you are going down this route, you'll likely get them cheaper elsewhere. Try and avoid eBay for mics though, quite alot of Oktava fakes on there.

NTG-1 is good for outdoor use, but you'll want a windscreen, ideally something like a Rycote, you can check this page: http://mymic.rycote.com/devices/ntg-1/ I would recommend something like the Classic Softie Kit. You can maybe find the parts cheaper, I think Rode actually makes a windsock type thing for the NTG-1.

The DR-40 is all you need (assuming you have an XLR cable to plug the mic into it, if not, then add one of those). My point was that you could maybe find a different recorder that had a lower noise floor if you were taking it back, but try it out with the mic first, if you can, that might make enough of a difference to keep you happy.

I have a mic grip for my shotgun mic, it is basically a shock mount, but one that's designed to be held, rather than mounted on a stand.

https://www.canford.co.uk/Products/74-225_RODE-PG2-R-PISTOL-GRIP-Shock-mount-for-NTG-1-NTG-2-or-NTG-3-microphone

http://puzzleaudio.com/field-foley-with-the-rode-ntg3/

https://www.amazon.com/Rode-PG2-Pistol-ShockMount-Shotgun/dp/B001GZ91MQ

​

Those should give you an idea what I'm talking about, even if the links are a bit random.

Best thing to do is imagine the most common scenarios you'll be in and prep for that. The pistol grip is pretty handy for me most of the time, but I think it mounts on a tripod thread (Euro mic thread), rather than a mic stand thread, not sure if that makes any difference to you.

I'm trying not to throw too much at you at once, you can ask away if you have any questions!