I stayed at the Penzance YHA June 5-7, 2009 and got room #16. The hostel is about a 20-25 min. walk out of town from the train station. I did it with my 40lb backpack in 25min. but you can take one of the city buses that will drop you off with in about 5-10min. walking distance, depending on how fast you walk. If you have a car it is quite a bit easier to get to the YHA but you're never walking through any bad areas except for having to cross a busy road near the end.
The hostel was just finishing its rennovation when I was there. The bedroom was comfortable, fairly large sized witha disused fireplace. The beds were comfortable with a reading light and the lockers were fairly large. If I needed to shove my backpack in I could have. The shower down the hall was good sized with enough room to comfortably dress in and had good water pressure.
The only problem I had with the hostel was I was not able to do my laundry there since they had not finished their laundry... more