No worries, it's fun stuff lol
If you've not had metalworking/weld prep experience I'd suggest chatting up an experienced welder, which isn't hard as all ya hafta do is find one & start askin' questions as most live to babble about what they do & all would rather stick something together that's been properly prepped. It's not difficult & mostly about clean, tight fitting joints but talkin' to them will also give ya an idea how experienced they are, how psyched they are to do the job & most of all, a chance for you to check examples of their work
My taddy is a bit complicated, it's not something I'd suggest for a first build & I mentioned the thread more to skim lookin' for ideas & links then to read through the years of babble page by page heh but hey, thanks for the interest & I'm glad yer getting something from it! It's... urm... bent bits and chunks from like three different wheelers? There' quite a bit of bicycle, a touch of go kart, a dash of street bike & moped both and then a whole buncha random stuff from anywhere I could find a dealie that was close to what I needed... heck even the headlights are re-purposed household interior lighting lol
For an introduction to fabrication I'd strongly suggest something w/a bit less chaos, the deltas rogergendron1 gave as examples would be the simplest, quickest way to get into it - although I'd prolly utilize the factory upper mounts these CRF50 clones often use & put the engine where it usually is mounted with the mopeds/dirtbikes & wheelers. They're just flat steel upper plates so I'd bridge the upper frame with a top tube, cut the lower frame out & weld in the CRF50 plate mounts instead, strengthening the frame for motorization & hanging the motor low, just like a ped. They even have a CRF50 clone w/pedals like a moped, prolly about as useless too heh but it'd be easy.
If ya wanted to try yer hand at making the tadpole style trike, or any scratch build this is a goldmine of ideas: http://www.atomiczombie.com/DIY%20Plans.aspx
, remembering any trike getting just about any four stroke other than a rack mount is going to be expensive or there's going to be some chopping going on, sometimes both lol - they're all pretty bulky engines & it's in width that makes a bike tricky, even the HF utility motors end up being roughly as wide as the CRF50 clones because of the aftermarket clutch/redrive, oddly they can end up costing more because of that if you're not careful...
...then again four strokes are the tool for the job for the long distance heavy lifting, their miserly appetites don't hurt either when yer talkin' cross-country so - is it worth the effort? Only you can call that 'un