Hair is being a problem for me. Facial hair, I don't like shaving (painful) (bloody). Not shaving it also sucks (prickly little growths) (spiky). Trimming isn't really sufficient.
Also, chest hair is being an issue. I don't want to try to shave it (that would be another level of hell). Trimming also leaves behind spiky hair that stings.
Hair growth on my head is going nicely. I like it. Then I think about how I will need to go to my parents during the summer and I don't want them to know about my situation so I am going to have to keep my hair relatively short 
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I've also started thinking that I should lower the dose of my hormones to slow down feminization. At this rate, I won't be able to hide my chest growths even with a breast binder. My parents want me to be over for basically the entire summer and I don't have a good excuse to not go. How am I to live with them in the same house while still hiding my feminization? 
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Presumably part of what's motivating you is also a strong drive to survive. This is a good thing and I wouldn't define the desire to survive as "cowardice."
When I met with one of my profs from uni post transition I told him "different name, different gender, same me" - and he gave me a big hug and shouted my new chosen name :) I wish that had been the story of my coming out to my mom. It wasn't bad or horrible, she just didn't say anything, we sat together silently and then I just left.
I'm not sure what's going on with your face that it's painful and bloody when you shave. You need to use a clean good razor, stick with the fewest number of blades - not 4 blades not 3, 1 or 2 blades. It depends on the coarseness of the hair - in the military, some people who have facial hair get shaving waivers because it's quite difficult to keep their faces clean shaven in a healthy way. But I bet if that's the case for you, you'd be a pretty perfect candidate for laser hair removal.
For your chest hair, you could pluck it depending on the number. E will eventually cut down your body and facial hair growth. You also could wax. Plenty of cis men wax if your parents ask, because not everyone is into chest hair.
You could keep your hair long and put it in a "man" bun while visiting.
I wouldnt advise cutting down your HRT. If you have to stay for 3 months in the summer, you probably won't grow that fast during that and if you already have growth it's not going to shrink them back. Cis people don't notice shit, you might be surprised what you can get away with. You could take a page out of trans guys books and try a tight sports bra or a binder - don't wear them all the time, it'll affect your chest development.