Nothing too build huge muscles just to keep fit, like 30 minutes every day or something.
i cycle everywhere at the moment but doesn't seem enough atm.
If you exercise in the morning without having a breakfast (ie porridge) there will be a chance of not having sufficient glycogen stores available for use. Not only will this mean that the time taken till fatigue will probably be alot quicker (espec. with HIIT) you may also use muscle stores (I'm assuming that you don't have much adipose fat due to daily cycling). Obviously this will be counterproductive to building muscle.
You could always buy a set of free weights to use in your room for general strength training.
You're limitd if you only want to work out in your room.
Crunches will just strengthen the muscles, not burn the fat.
HIIT is your friend - a gut busting session done in < 30 minutes - good way to start the day.
I don't think many athletes get to where they are by just working out in their room.
I personally wouldn't recommend doing any cardio first thing in the morning without a decent breakfast, and from personal experience evening is much better, but obviously everyone is different. Try different times yourself and see what you prefer.
If your primary aim is to lose weight then as suggested above HIIT, is your best bet. This is probably easiest to do at the gym on a treadmill/ cross trainer, where you have control over speed/ timings etc.
But if you're not a member then sprinting outside in short bursts, then jogging slowly would also work. If you live in a hilly area try running uphill, then jog slowly down, and do it all over again!
Weights can be used for general strength training, but won't help much with weight loss.
I can completely relate to this! Maybe go along with a friend who is already a member, and only join for a month to start with, and see how you find it. It's is probably one of those things that once you've been, you'll wonder why you were reluctant in the first place!
But you can still get fit without going to the gym. I've would consider myself to be reasonably fit (resting heart rate of 58-60bpm) and have never been a member of the gym (though I do have access to a treadmill). I run, swim, cycle and do strength/weight training regularly, and except for the swimming all of that is free.
I CANNOT recommend running enough...I love it. Running outside is much harder because of the uneven terrain and weather conditions, but much more enjoyable in comparison to treadmill running.