What workout would be complete without planks? You can do them on your elbows or forearms, making sure your back is straight, and holding the position for 30-60 seconds with your core tightly engaged the entire time. Next, come side planks that work your core's oblique muscles. Lay on your side with both legs extended and lift up from your forearm, holding the position for about 30 seconds before switching and doing the same thing on the other side, per Smarter Travel. 

You can even try what's known as a Dolphin plank, which can be a very effective ab workout. To begin, get yourself into a traditional plank position on your forearms. Then, press down through your shoulders and arms while lifting your hips upwards, before lowering back into the plank position. For optimal results, repeat this 15 times (via Shape).

Finally, get those calf muscles in shape by doing heel lifts, which are as simple as they sound. Simply lift your heel, then hold the position for a few seconds, and lower. If you feel strong enough, you can do heel lifts holding onto nothing, but if you need stability, grab onto the back of a chair. Do this for 12 reps and your hotel room workout is now complete.