I definitely know that strategy. I got some good practice going after the only Unova roamer in Tornadus (Thundurus in White). I knew I only had 5-10 minutes by the time I unlocked his reign of - uh - terrorific weather (it moves to Routes 12-15 at midnite), so I went just for weakening without thinking. Overnite, I realized Watchog still knew Mean Look - something I had somewhat planned on but not thought about until that moment. It also knew Hypnosis and Super Fang. A perfect combination.
It did get knocked out once (and predictably, after the knockout, the roamer resumed roaming). The second try turned out much better, lowering to the single HP and - because it was dark - snagging in a Dusk Ball. At least, I think I used that, I'd have to go back and check.
Haha, I don't go to quite the extent of catching so many Pokemon and training them all, but I usually have about 10-12 that are ready to go at any time, that I switch in and out of my party as I see fit.
Also, if you're looking for the legendary beasts, it might be a good idea to have something that can either paralyze it or put it to sleep, too. Sure, they'll run away after the first turn, but every subsequent time you find them they'll still be affected by it, and I found that it made them a little bit easier to catch after that.
Haha, I am most certainly not you, but we seem to have similar playing styles. One note for me is I literally try to catch every Pokémon and train them to their full potential, then decide what I like for the next stage of the game. In this case, I have three Psychics ready for the Gym, but I'm still four Gyms from completion and am training the entire PC. As time goes on and fewer Gyms remain, I'll likely concentrate more on those specific Pokémon. I do however have an objective of taking on the legendary roamers, which are all Lv.40; for now, I'm trying to lead into such encounters with Quick Attack at the ready. I did once use Bind and struck first, kept it from running, then got stomped out in one hit; won't do that again. :D
Wow, are you me? Throughout most of my playthrough of HeartGold, my Typhlosion was second or third fiddle at best, and by the time I got to the Elite Four, it was only on my team because I didn't have anyone else with Fire-type attacks. Almost as soon as I finished with the E4, I put my Typhlosion into the PC in favor of my Smeargle which knew Flamethrower.
So you're also a Fire starter, yes? I have my Quilava raring to go, and it's fallen slightly behind in leveling, so I have to give it more level-up priority in the next areas where water is not involved. Typhlosion will become a key member of my team going up to the E4 with time, but once I reach the E4, I might have other plans.
If it hadn't been my goal to get my Butterfree to level 100, I had my Girafarig as back up against Chuck, too. I think I ended up just using my Typhlosion against Jasmine, but that would also be a good place to train a Nidoran (part Ground) if you did end up using one.
Haha, I actually have a Butterfree (Bug-Catching Contest FTW!) and have thought about using it, but also have a Drowsee (which is rather weak compared to its compatriots), Kadabra, and a very strong Girafarig on standby. I don't think that Gym will be a problem, and once I head there, it'll be an easy matter returning to take on the sixth Gym, and my Machop (later Machoke) is one of the Pokémon I'll have ready for it given that its type is the weakness of the two Pokémon presented by the leader. I'll probably take a water type to start against the Steelix and a ground type to counter the electric attacks of the two Magnemites.
I always thought that it was strange that Nidorina/Nidoqueen couldn't breed at all. I figure it must have been a glitch or a programming mistake from G/S/C that they just decided to stick with in future games.
And good idea with taking a Psychic-type into Cianwood. I think my Butterfree single handedly swept the entire Gym with Psybeam (and an occassional Sleep Powder if needed).
I was lucky to have my (then) Lv.64 Swanna with me with TM moves learned of Surf, Fly, and Dive; I'm not sure, but I think it was Fly that finally took down the Lapras in this battle. It creamed everyone else in my party.
I'm currently working on leveling and such in Soul Silver, I plan next to get that game finished. I'm purposely spending time leveling up everything I can to the 20s at a minimum (with possible exception to the Nidoran, whose evolutions cannot breed at all, until I go to catch two more in the Repeat Balls I snagged from the Prize Corner - or perhaps find the second evolutions in the game somewhere). Once that's done, it's off to the Lighthouse to give me access to Cianwood, then my Psychics will have a field day over there. :D
I just recently beat White for the first time, and tried to do the exact same thing as you by avoiding the sight of trainers and just getting to the next city. If I hadn't had type advantage over the one trainer that saw me with level 65's, I would have been destroyed since my team was all around level 49-50, with only my Sigilyph at 54.
Hahaha - that was a huge level jump in the eastern maps indeed. I went swarm hunting after managing to unlock every city (with careful trainer avoidance most of the way) and tripped the gaze of a trainer on Route 14 who started with a Lv.68 Purugly; I had with me six Pokémon under that level, and my leader was a Lv.48 Musharna as I had just activated a Repel to go Yanma-seeking in the grass on Route 14.
I will never forget what happened. I survived the first hit and activated Hypnosis, followed by two Dream Eaters. Purugly was unable to continue batling, Musharna was the winner. I still can't believe that.