It is hard to tell without pictures. What are the tub and fixtures like, are they serviceable? You said horribly outdated vanity...is it in good shape? I am in the middle of a similar whole house project and am trying to keep realistic stopping points. In my kids bath we had the floor tiled, gel stained the vanity, added a shower door, replaced the toilet, painted and added a granite remnant counter with undermount sink. We did not replace the tub or builders white tile surround. Total cost was under 1K and the bathroom looks great.

As gmp3 said, some more specifics and/or pictures could be helpful. You could make some changes initially like stripping the wallpaper now. Other changes, like flooring may need to wait until you're ready to do a full remodel (depending on how you install the floor).

If you do wait, what is your timeline until you are able to come back to do the full remodel you want?

I am slowly remodeling rooms in my home, tackling the worst first. Until I remodel the room completely, I only tackle things I can carry over for the remodel. For example, I purchased new appliances when I needed to replace my old ones, knowing that I'll use them when I remodel the kitchen (floors, cabinets, counters, layout, etc). My master bathroom is tolerable but nothing to be proud of. But I will be leaving it as is until I can do a full remodel. Everything mostly works (broken vanity drawers, no sink stoppers, few cracked tiles, etc), and it isn't worth my time or money until I can do the full remodel.

I agree. I am often hesitant about spending money, and my husband has no interest in decor, so we tend to save money by living with ugly things until we are ready to re-do the entire room. For example, I think it'd be a waste of money to get a new floor, only to rip it out later when you get a new vanity. I'd strip the wallpaper and paint, as that's cheap.

We had the same situation several years ago. We stripped the wallpaper, painted the walls a pretty color, painted the vanity white, and replaced the vanity hardware with inexpensive knobs that updated the whole look. We also chose accessories we liked, soap dispenser, tumbler, etc. It made a world of difference for very little money. In fact, it made so much difference that we are just now doing the major renovation. Cosmetically, it was still fine, but the fixtures are now just plain worn out. We liked the accessories so much that they are being kept and the new color scheme uses them as the inspiration.