Alternatively, you could temporarily turn the difficulty down in the menu?

Isn't that cheating?

No, using http://www.nma-fallout.com/forum/dload.php?action=file&file_id=52 would be cheating, lol.
I can't tell you exactly what to do against the deathclaw mother if you're struggling. Perhaps get your mitts on some grenades?
Burst weaponry?

Darn, I was so closed! I had chipped of almost 300 out of her 350 health. Ian and Dogmeat had left the fight and me and Tycho were hitting her over and over - and then she killed me. Annoying!

Ah sweet memories... That fight is one of the most challenging in Fallout. And I'm not sure that using Combat Shotgun is a good idea at all. Even with heavy weapons it could be hard. If I remember correctly, the best weapon for taking down Deathclaws was Alien Blaster.

I don't recommend taking first aid or doctor skills, because you have ample time to finish the games. 13 years is the limit in FO2, I believe, and I beat it in like two putsing around. Just rest when necessary and save your stimpacks and super stims for when you are in big battles that you can't get out of quickly.

Heh, yeah, I would believe the Alien Blaster is the best weapon for taking down most enemies.

I've managed to kill the Mother Deathclaw now, and am wondering what level you should be to try and kill the Master? I'm level ten, soon to be level eleven now. I was thinking I should wander around and do some quests here and there until I get to level 12 so that I can get another perk, and also so that I can stock up on Stimpaks. Is that feasible?

What weapon should I have for doing the last bit of the main quest? I have a Combat Shotgun now. I have 11000 caps now. Should I spend them on SPECIAL-upgrades over at BoS, or is there some awesome weapon I should buy somewhere instead?

The master can be killed with out even firing a shot, you don't even have to see him if you don't want. But if you do want to go toe to ..um.. (toe?) with the master the alien blaster can work, but it does have limited range. missile launchers are fun, I've also used power fists and supersledges on him. It's meant to be a big bad final battle so it's not supposed to be easy. I would suggest questing around until you hit the level cap then go and see what's what with the master.

Not to start a fight but I almost always tag Doctor. I sometimes like to leave a fight and heal myself instead of using all my stimpaks. For example if I run into a cave full of raiders I can fight them near the entrance and when my health gets low I can step out and heal then go back into the fight. If I were to rest until healed then the raiders would also heal during that time, but if I doctor and first aid my self then they only get a few hours worth of healing, plus using doctor and first aid nets you XP.

I tried entering the Cathedral, but I think I have to face the fact that I'm underlevelled at level ten. *sigh* Ian and Tycho died in the Cathedral itself, and me and Dogmeat are now underground.I died fighting off two supermutants, two flowers and one centaur at the same time. I know I can win over the master without firing a shot (which I'm going to try), but I am not sure I am able to get to him at this stage. I haven't had any encounter to find the Alien Blaster either.

Why are you fighting them? Just leave your companions outside, then put Children's robes on and the guards will let you pass. You can get to the Master without a fight.

I do have a robe, but I got Dogmeat with me. I can't tell him anything, that means I have to kill him.