I'm going to start Limited Items Challenge in Crystal. I'll update my process after gyms and other important parts.
If someone else is trying this, it's good to know that there's only two Pokés that can learn Waterfall before Tohjo Falls where it's required. In Gold/Silver, you must get a Dratini from Goldenrod Game Corner. In Crystal, you can also get a Water Stone from a fisher in Route 42 (or was it 44? I'm not sure) and evolve Eevee with it.
Process Update:
TOTAL PLAYTIME: 0 hours, 33 min.
I got the Pokédex, beat the red hair guy, and beat the first gym! Current party:
Totodile LV.13
Togepi egg
I think that's enough for today.
Process Update #2:
TOTAL PLAYTIME: 0 hours, 58 min.
I made it through Union Cave. Totodile evolved in the Slowpoke Well, and I got through the Well. No KO's yet
Current party:
Croconaw LV.19
Togepi egg
Process Update #3:
TOTAL PLAYTIME: 1 hour, 22 min.
I completed Azalea Gym, beat the Red Hair Guy again and made it through the Ilex Forest. I taught Cut to my Croconaw and got the Odd Egg and Bike. Current party:
Croconaw LV.23
Togepi egg
Odd egg