When i saw that you were in the St. Louis area that intrigued me, as I too am in the St. Louis area. When I saw that you were in Illinois and 20 minutes away from St. Louis I got scared, as I am the same. Although the fear instantly dissipated after remembering what a fellow lawn care professional had said to me when I was considering start up. "there are plenty of lawns to be mowed, so jump on in, and don't be scared to take some work from someone they will always be able to find more!" With that said, I am not sure exactly how beneficial I can be to answering your question; but here it goes.
I started up this year using a mini van, a 1 year old troy built self propelled push mower, worx weed eater, a battery operated leaf blower, a very old edger, a plastic dust pan, a 30 gallon trash can, and two wooden 2x6 boards for ramps because lifting the mower into the van was not happening! I quickly learned that the battery operated way was not the way to go even with purchasing extra batteries, because the charge time was way too long. I then returned the blower and purchased a prolaun blower, and echo weed eater (kept the worx for home use, I love that little piece of equipment not to use it) The blower was supposed to have the capability of mulching the leaves which it did half way through the first attempt. then the blades on it which are some sort of plastic material, began to chip and grind away which left it basically worthless to use as a mulcher, and later this season it became difficult to keep running. Not professional grade at all! If you can get by purchasing something better on that end do so, if not the prolaun will work for at min one season only for blowing. As for the mower I have had a fondness for troybuilt since childhood when I mowed our one acre lawn with a push mower. That thing is a titan! Lasted all year! and still going strong! So as far as doing lawns with a push mower to start with is completely do-able! I ended up taking a lawn from another lawn care rep, due to as the customer put it crappy service, she ended up donating her john deer rider thinking that it needed a bunch of work, when all it needed was a battery (i offered to pay she said no way, I can't use it anyway) a riding lawn mower worked on her property since the size of it was so large but would not recommend it for smaller lawns, although it will work it is more of a hassle than anything. Taxes I am planning on purchasing a zero turn and some other much needed equipment as for what kind i do not know yet, although I am having a bit of an issue with deciding because most of the residential lawns where I am have a bit of an incline in the front lawn which i believe will be difficult with a zero turn although i have seen several of the trailers around here have them so I am not sure how that works i have never seen them in action only driven on a trailer. I am considering purchasing a stand on model of some sort as some of the research i have seen seems that they handle the inclines better, and they can be purchased in a larger width as well. As for the trailer i did manage to get a trailer this year that i purchased from trailers plus in mo it was a bit of a drive though can't remember off the top of my head exactly where it was but the guy worked with me and i love my trailer i bought it new after seeing that there were hardly any trailers used on craigslist and most were close to the same price as a new one. I purchased a 5 1/2 x10 utility with a gate. My suggestion, get an enclosed trailer, with swing doors and get some good ramps. this is a personal preference for two reasons. I don't have anywhere to safely store the equipment out of the elements, and theives unless i chained each item to the trailer and tarped it every night and that wasn't happening so i have to rent a storage facility which is kind of nice because it provides extra storage for other equipment that isn't being used at the moment, like the snow blower, and other stuff... also the swing doors seem to me now like a better idea because me with a bad back which is kind of what lead me to lawn care anyway, it is really difficult to lift that gate over and over through out the day. Get the largest one you can to start off with because you will eventually need the space. Save money where ever you can to keep your costs down this is where you will get the most customers. I ended the year with only having 10 customers with which i gained through only door to door flyers hung by a rubber band. I only hit a few streets deliberately to test the waters so to speak. This way i wouldn't get overwhelmed with it and end up having too many to handle and crash and burn before i had a real chance this way it would give me the ability to make a little money while learning the ins and outs of starting a business. If you have an income source i highly suggest keeping it for one year before you dive in head first. Figure out the business side of things. How will you determine your prices? Figure up your running costs if your hiring people the amount you want to make, the amount the "business" should make and so on. There are several ways of doing this and honestly you will end up having to figure that one out on your own. I highly suggest not eye balling the price. Payments set up some type of invoicing system. collecting payment at the door when service is completed seriously sucks! I did that all year, and with some I had to come back because they were sleeping, or what not, that was a waste of time and gas so next year i plan on doing a monthly billing system. You can either ask them the day that they choose or pick the day yourself. Picking the day may be best and sticking to it. hope any of this helps.