What do you mean by 10k, 20k, 30k, 40k and 50k tasks?
I didn't mean to write that. That was dumb of me. What I meant was that I need a place to keep track of the things that would make up my runway - 50k. The responses in this thread seem to have made some good suggestions.

I guess as upper altitude stuff can always be made into additional tags in evernote and I can just keep track of them there.

Thanks all!