you get what you pay for. although this site isn't free since we have to post for credits, it's free in the sense that no money is being exchanged. now i have personally searched for free hosting before and decided on trap because of the services and resources offered that most free hosting accounts don't offer. again, you get what you pay for though.
now my advice is to apply for hosting right away! decide later if this site is right for you. although you have 100 credits, those are nothing compared to what you will need if you plan on hosting your site here for a few years so apply now, decide later so you don't have to waste anymore credits.
your complaints are valid and i say that because i know you are not the first person to complain about the credit system and some of the vagueness in the readme's. but again....you get what you pay for

i say suck it up and learn how it works as you go along.
i know you are looking for a reliable host. i was anal my own self when searching for a good host and aside from the very few complaints trap has, it is a great host. many advantages that you wouldn't normally get with any other host.
now i know the credit system is connected to the hosting but try to seperate it. post because you like to post not because you need hosting. if can't seperate it, posting will become a chore and hosting wont be fun for you anymore here.
also know something about your credits. it's easier to collect credits faster when you have fewer credits banked. the more credits you have especially over 100+, i've noticed it's harder to collect the same amount of credit compared to if you had only 10 credits banked(a very few amount). what this means is you have 100 credits now. it will take you longer to get to the 200 mark compared to when you get hosted and getting back to your 100 mark. trust me. you can get to 100 in a day. it's not that hard

especially if your wife is connected to your account. now this really isn't very well known but i thought i needed to tell you that since you want to be up front on everything so you don't waste your time.
i wouldn't wait for 280 credits for your domain name and spend the rest towards hosting. i believe the rules state you have to be hosted FIRST before you can apply for a free domain with credits. everything really is in the readme's and i don't think anything is in fine print as you tried to point out. they just need to be read and understood but not a lot of people want to take the time to read the readme's. also, transfering 70+ credits wont do you any good since you also have to be hosted FIRST before being allowed to transfer credits.
with someone so concerned about losing his site, i'm surprised your not going to paid hosting. i'll tell ya this though. if you lose your site here, you will lose it anywhere. i'm pretty shocked you already lost your hosting just by trying to complete a backup. if you were more specific to what you need to do and what your site is being used for, we could probably be more able to help you determine if the free host route is your best option. otherwise, you are limited to your own good judgement in what you think is acceptable when your site will be one of 100's in sharing the same resources
with that said, hope ya find a home here. it's a pretty good place overall and posting has never been a chore. a great opportunity to get hosted and belong to a community of some really cool people who will always be open to talk to ya and help ya with any problems you have.