About
saddles, in general:
A wider saddle means more rubbing on the thighs because there is essentially no room to spare between human thighs. But there is less pain because your weight is spread out over a larger (and often softer) saddle. Like so much in life, you choose your preferred compromise.
Let's get rid of one type of saddle right away: The last few years a new style saddle has come on the market with NO HORN. That is, there is no pointy part on the front of the saddle. I tried one. I darn near fell off. Turns out, that horn is there for a reason -- to keep our body aligned with the bicycle. Without the horn our body will easily twist out of line with the bicycle and we go ass-over-applecart.
This brings us to the tilt of a normal saddle: It needs to be tilted a bit up in front. That seems counter-intuitive to a person who sees a bicycle for the first time, but that's how it works.
Now: Some of the "cruiser" saddles these days curve upward at the rear. Presumably this is intended to keep us from sliding off rearward -- or at least to follow the roundness of our butt to improve comfort. I've tried this too. Horrible -- at least for a big guy like me. Maybe it would work for a small person.
Be sure to adjust the saddle high enough. Most people have their saddle too low. This is harder on the legs than it needs to be. Sitting with one pedal straight down, and the ball of the foot on the pedal, you should be able to extend that leg fully by tilting your heel down.
Handlebars & cables:
I swap out handlebars all the time -- I install tall BMX bars on all sorts of bicycles. For cables I buy a set of four cables -- both jackets and wires -- from one of the discount department stores. The set costs something like six bucks. These cables are plenty long and you cut them to fit. The wires come with different shape ends, so be careful you don't cut off the end you need! Last I looked, the Bell brand had unlined housings, and the Schwinn brand had nylon-lined housings which I recommend. Be sure to use the ferrules and tips that come with the kit. I highly recommend a "serious" wire-cutting tool -- not your general bailing-wire clippers. And spend some time to make sure the ends of the housings are smooth inside after you cut them.
Decent bicycle stores can also sell you cable housing (jacket) by the foot, and individual wires which are good and long.
In a couple of extreme cases where regular wires were not long enough, I used wires for tandem bicycles. These you have to get at better bicycle stores, and they cost a bit of $$.
One last thing: There exist shifter cable housings that are made of many thin straight strands of steel, instead of the normal single strand of coiled steel. Supposedly they give more precise shifting with the kind of shifters that make clicking sounds. Well, shifting is a full-time-exercise-in-clusterblundering anyway, and specially so with clicking shifters (in my personal opinion). I have learned to avoid the straight strand housings like the plague, because they fail so spectacularly.
What did I miss?