Totally agree on installing solid color lines..... they don't necessarily cost more...depends where you shop and what brand ..... but even if you pay 10cents a foot more, they are worth it to reduce the confusion factor. Sometimes your guests don't want to learn everything about sailing the first time out.... so in a pinch you can just say "the red one".... but even without guests, it's just easier for you to locate or straighen out the control line you need. And you can still label the cleats and stoppers.... In any event, contrary to what centerline says, colored lines are widely used by all of us...... racers, cruisers and daysailors.... they just make sense.
I also totally agree with Chris, that a tiller pilot is the best single investment you can make if you plan to single hand a lot.... and even if sailing with crew most of the time, a tiller pilot is very functional...
And this brings us to the oft discussed tiller/wheel conversion. I'll say this, DON'T DO IT! It's very costly, and will actually make your 25 footer less amenable to single handing. First of all, a tiller pilot is way, way cheaper than the least expensive wheel pilot.... For your boat you can purchase a Ray TP1000 for under 450.... even less if you shop... Second, and I single hand all the time, you can easily handle the sheets and halyards AND steer the boat with the tiller between your knees.... the tiller allows you to move around the cockpit for the most desirable steering position.... especially if you have a removable extension you can mount to the tiller....like if you want to sit on the upwind side coaming, well forward so you can see the jib telltales, or oncoming traffic... etc... The tiller gives you much more sensitivity to your boat's motion and the elements affecting it, in addition, when not sailing the tiller lifts up, out of the way to give a small boat more cockpit space.... can't do that with a wheel. Finally, a wheel on a small sailboat is unnecessary from a mechanical standpoint, and... in my opinion.. just not aesthetically pleasing. Oh, one last thing, you will not get your investment back when it's time to sell the boat.... in fact, the cost of adding a proper wheel steering system will probably be more than the total value of your boat now.
Back to single handing.... By all means, run your halyards, cunningham and vang controls aft... pretty easy to figure out by looking at a few pictures. Note than even though rope clutches are pretty cool, they are fairly expensive. Cam cleats great, but if you're on a budget, simple vee or "clamcleats" are more than adequate... it's your money.
If you use hank on sails.... install a jib down haul.... very inexpensive to set up.... it's been discussed here so if interested, do an archive search or send me a private message. The jib downhaul will allow you to drop your headsail on deck in any condition, from the security of your cockpit.
The final recommendation I'll make is to purchase a safety harness and good quality tether...... and use them at all times when sailing solo...... Even on a placid lake, getting separated from your boat is not an option.