Here is a web site with great information on laying out a bathroom. There is other good info too, but I've used the info regarding spacing between sink and toilet that are across from each other.

My bathroom project is 7.5'x9.5'. It is an existing bathroom but things got moved around a bit from the original layout. Here is my floor plan:
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Anyway I hope the website is helpful:

Here is a link that might be useful: Illustrated Rules of good bathroom Design

shower/tub going up/down on left wall, starting at "top". Toilet next to it, directly across from door (not ideal spot, but it is where it fits, unless we can find more space).
30" max vanity (probably more like 24-27") in the lower left corner...

If you go with a short tub (and you can't get 6 more inches on the left long dimension), then here is another option:
Tub/shower (short) on the long wall, lower left corner. Toilet in upper left corner, facing the right wall.
Vanity opposite toilet in upper right corner.

If you had 6" more (96" on the long wall), you could easily do this with a full size tub. But, you need a minimum of 30" of width for a toilet...so will need to go with the shorter tub.

Can you move your door to the middle of the "lower" wall? If so, what about the tub/shower combo along the top 86" wall, with the vanity on the left wall as you walk in, and the toilet on the right? You would need a pocket door ideally. Assuming your tub is 30" wide, this leaves you up to 60" for a vanity and 60" for a toilet across from the vanity. A window would work on the vanity wall, perhaps at the end of the tub?

If you're talking about a separate shower and separate tub, I think it's possible but might feel cramped. Tub+shower along left wall, toilet in upper right corner, pedestal or wall mounted sink right in front of the door.

I agree that shifting the door location would help a lot. Even making the door swing out, or putting in a pocket door, would help minimize the crowding.

I have a similar sized room that I've really struggled over. It's 100" across and 90" top to bottom. I ended up going with just a walk in shower that's 36"x48", because we really wanted a separate shower, and any plan I came up with that included a tub left so little room for a vanity or storage. I'll try to post the diagram of my (I hope) final design. That's a shower on the right and linen closet on the left of the door; I'm hoping to turn it into an outswinging door.

Thank you all for your time. Unfortunately, the door cannot be moved and there is no where else to obtain a few more inches. The second option Kirkhall describes is what we have been able to come up with also, using a 54" tub. If we do use that option, I'm considering putting a small window over the back of the toilet. I'd really like the window to be on that wall if possible.

Thanks again for your thoughts.

Another option that could work with the door location is 56" tub on upper right 86" wall. Toilet next to tub on upper wall, with about 30-32" width (36" is ideal, 30" is the minimum). 42" vanity on lower wall, to door. Window between vanity and toilet.

If you skip the tub and go for a shower only you open up quite a bit of space. Good luck.

How about a sliding door?