Hi nwc01,
The Sunrace 9 speed cassettes fit Capreo FH700 hubs. They are made for them. I have a Capreo FH700 hub with 9 speed cassettes and shifters. The Sunrace cassettes work beautifully. They are still available from Soma Fab at the link at the top of this thread. Don't know if they will ship to the EU.
Is this all that I need?
Yes. No further parts are necessary; although you will need a chain whip, and a Capreo cassette removal tool to replace the cassette. The Capreo tool is a special one that fits only Capreo-compatible cassettes. It is possible to remove the lockring without the special tool, I've done it many times (with, I admit, a high degree of difficulty) using vice grip pliers, but it's much more convenient and easy with that special tool. (Well worth the price.) Most bike shops don't have the tool, either for sale or on the wall for their mechanics. They were unavailable for quite a few years, but they're back in stock these days. I just searched on line and found quite a few for sale for about $15. In particular, Performance Bike had them. (I'd post a link, but am not allowed by the Bike Forums.)
Will it fit with the Shimano Capreo FH-F700 hub,
Yes. 100%.
or do I need any other parts?
No. All you need is the cassette and the tools to get it on and off. It comes with a new lockring.
Are there better alternatives (more widely available, with similar gear range, a little less range would still be OK) that would fit on the hub, or would I need a new wheel, hub, cassette and shifter?
I haven't seen any other replacement cassettes that fit the Capreo hub: (although I must admit that I haven't searched for one since I bought 3 of the Sunrace cassettes in April of 2024.) You can replace some of the cogs (I think all but the smallest 3 or 4) with 9 speed cogs from any other Shimano compatible cassettes. More on that below.
As I said in my first post, I was about to give up on Capreo, because my last cassette was wearing out. I would have had to get a new 9 speed hub and lace it into my wheel. (I like building wheels, so no problem for me.) If you don't know how to lace up a new wheel, or don't want to pay someone to do it for you, you'd just have to buy a new rear wheel with a 9 speed hub. No need to replace your shifter, unless you're dying to switch to a 10, 11, or 12 speed system.
When you say "the first three gears are worn out," do you mean the large cogs that give you low gears for climbing, or the small cogs that give you high gears for going fast?
If it's the large cogs, you have another option. You can replace just the three worn out cogs with new similar sized cogs from another cassette. Almost all 9 speed Shimano-compatible cogs will fit. The only problem is that there will be a difficult shift, when transferring between the last of new cogs and the first of old old cogs (and vice versa.) That's because Shimano cassettes use cogs that are specifically designed (with specifically placed little ramps and shaped teeth) to work next to each other. If you put on some new cogs from another cassette, the last new cog won't have the right ramps and shaped teeth to mate up perfectly with the first old cog. This doesn't mean you can't shift across the boundary, but the shift won't be butter smooth. I currently use this kind of set up because I want bigger low gear cogs than those that came with the new Sunrace cassette. I pay for this by having to fiddle with the shift every time I cross the boundary between old cogs and new. I can always make it work by double shifting over the boundary and then single shifting back to the cog I passed over. Frequently, it works without needing that, but I always have to be prepared to fiddle at the boundary. All the rest of the shifts (from new cog to new cog and old cog to old cog) are smooth and easy as expected.
If it's the little cogs (the high gears,) those are Capreo specific and nothing else will fit.