In absence of a good gym it is important to keep the body getting the right stimulus. Not in order to grow but the keep atrophy away as much as possible. So it is important to understand that proper muscular adaptations are difficult to get due to the fact that there are not a lot of possibilities in terms of exercises or progressive overload. During these times the toolkit of exercises you have significantly decreases and if you are for instance, not good at bodyweight exercises like pull ups or handstand push ups the toolkit decreases even more.
Nonetheless it is very important to keep training but it is in your best interest to understand which kind of contractions should be invested in these times. To further explain this you first need to understand muscle fibers and their function.
As you see in the example above, we have multiple muscle fibers, the amount of resistance dictates the amount of muscle fibers needed to complete a particular task. There are different ways we can contract the muscle. We can do it in an aerobic fashion, like you´re doing right now. the muscles in your body are working to keep yourself upright or if you are walking the muscles in for instance the hamstrings are working to get you to move forward. But these contractions are not with high amounts of resistance which will cause the body to use a lower amount of muscle fibers. This is called rate coding. Basically (in a ideal situation) the more load we lift or the more speed full we contract, the more muscle fibers are needed to complete the movement. During disuse of heav(ier) or speed full contractions the muscles don't get the stimuli they need in order to increase in capacity or to slow down/stop atrophy from occurring.
So squatting with 2 bottles of water when your 1rm is 150 kg has not much impact because the body does not need a lot of muscle fibers to complete the movement. This in combination with increasing dose of endurance training often times result in a drop in strength because the body does not use it (use it or lose it).
What can you do?
I would advise to maintain the same ratio of contractions that you do during your normal training. That means that if monday you usually do: snatches and back squats, you can try to replicate these contractions via weighted jump squats and heavy wall sits. This way you can keep declination in strength out the door and get back on track as soon as you are back in the box.
It is not advised to do heavy contractions if motor control is not on the right level in the first place.
Knowing this information you should have an idea as to what you should do when you do not have access to a full gym.