I agree with Rustedbird on the caulking and painting.
In my experience I have dealt with a few concrete block houses and had good results. One had a flat roof, steel windows, painted concrete block on the outside and inside. It had been built for the lowest possible dollar.
We replaced the windows with aluminum, insulating glass double hung windows. We put rafters over the existing roof and made a 4/12 pitched roof with fiberglass shingles. We put vinyl siding on the outside by drilling a hole every 16", installing a plastic anchor and screwing the vinyl to the house. Put in new doors and storm doors.
I pass the house occasionally and it still looks good from the road; no missing vinyl or anything.
On another one I concentrated on the inside; putting up paneling on wood strips. It was a bad experience which I wasn't too proud of. I think the house has been torn down now; good ridance.
Now, back to your house; there are several creative ways to upgrade the house. You could use almost any finish on the outside; stucco, vinyl, hardy board or even a cedar siding. Just remember, masonry attracts moisture so it will need to be something that will stand up to that. Some replacement windows, even if you only do one at a time you'll be that far ahead.
On the inside you could use paneling, drywall, plaster, or block filler and paint. The block filler smooths out the little holes in the wall and makes a somoother painted finish. I would use a semigloss latex enamel to finish the inside because it looks fresh and new for years longer. Even the wood ceilings, if they are in good condition could be painted again for a low cost finish. Then, when you get ahead a little more you could cover the wood ceilings with drywall.
On the plumbing side, many older homes used a combination of cast iron and galvanized pipe for drains. If that is your case, the cast iron is probably still good but some of the galvanized pipe may have given way to draino and rust. You can usually unscrew the galvanized pipe and replace it (even with plastic pipe) to renew your drains. Then you could replace the fixtures one at a time to update them.
Here's the thing about it; there are plenty of professionals on here and many who have learned by doing their own to walk you through each project. Have no fear, just start saving the pennies and keep in touch; we want to help.