Knuttle - mebbe an option for you to consider would be a wheeled gas powered string trimmer. Several brands out there, but >$200 new. OTOH, they just don't wear out.
They feature a briggs 6 hp 4 cycle engine - reliable, power to spare. Heavier .155 dia line for better wear, heckuva lot easier on the back/legs to use, IMHO..
Might hafta drop some crushed rock in that ditch bed amoungst those stones so as to be able to use rig there..

Here is a link that might be useful: wheeled string trimmer

Just got out from under 15+ years with a Ryobi 4 stroke trimmer. Great power and GREAT weight. Hard to get it to run correct at altitude and the string head was a HUGE pita to reload and constantly jammed the string.

After a lot of research and talking to people I bought an Echo SRM-225 2-stroke. Was on sale in June for $199. It has the slickest string head... Speed-Feed that I've ever seen and it's really lightweight and EZ to hold and carry and has a 5 year residential warranty.

I'm more than satisfied.

BTW, I'm using the pre-mixed non-ethanol stuff you buy at Home Depot for $5 a quart. Couldn't be easier.

As far as oil in the carb... there's no float and bowl in a pumper carb so it works fine and I'll wager you'll never see a pro lawn service with 4 stroke trimmers.

I'll throw in that a little bit of oil never hurt any carb.
I don't know where you were given that notion but it is not valid.
The enemies of carburetors are water, stale gasoline, and varnish. I personally do not like the ethanol blends, but it's the law where I live.
I have used about 5 cans of the stuff jal refers to (since I first saw it 2 years ago) and have seen no problems ..........except I feel faint when I realize I'm paying $20 a gallon for fuel when I buy it.

"... except I feel faint when I realize I'm paying $20 a gallon for fuel when I buy it"

Weed wackers aren't gas hogs so a quart goes a long way. No buying 2 stroke oil and having to mix.

That canned stuff also burns real clean so decarbonizing is done at far greater intervals and since there's no ethanol in it the carb runs a lot longer before needing a $25 rebuild kit.

IMO, the canned stuff is worth the $$$ in the long run.

OP: $20/gal for gasoline just so you do not get the alcohol. I am just waiting for the next green idea. For every gallon of pure gasoline burned you get the equivalent of one gallon of carbon dioxide. For every gallon of ethanol you burn you are putting the equivalent of 2 gallons of carbon dioxide into the air, one during the production of the alcohol and one when it is burned.

And the greens tell us carbon dioxide is bad.

I'm not concerned with the carbon footprint of my weed wacker.

I am concerned with half open 2 stroke oil bottles and stale 2 stroke mix that will gum up my trimmer so it won't start when I want to use it.

Life is always a compromise and I choose to buy a quart of redi-mix for $5 that has a shelf life of at least two years unopened and one year after opening. Come to think of it... the gas and mileage I save by not driving my truck to the gas station to get fresh gas to mix up some 2 stroke mix for my trimmer when I want to use it is more environmentally responsible IMO.

Echo SRM-225 is a good choice... check one out.

See the linked thread below. I bought an Echo (seemed like a lot to pay at the time) and it was one fo the better pruchases I've made recently.

Here is a link that might be useful: link to discussion on Weed eaters