I used to change the tie rod ends on my Ford Tempo commuter car and set the toe, myself. Not extraordinarily hard to do but without the precision of a big machine it was necessary to make some minor readjustments to get it correct.
There is a pretty narrow window on toe adjustment before too much toe chews up the outside of your tires. The factory max is really about it.

fixx
 

this is what you do,,figure out your tougue weight with each trailer, load the back of the bed with the desired weight, add a set of rear air bags,go to the aleignment shop and add air to the bags until the aleignment shows the factory specs and remember the amount of air per trailer...makes a huge differance..

I highly doubt that the weight of your new 29 Islander will even move the alignment out of spec. It maybe has a 1000lbs of tongue weight and will barely make the rear drop.