Forget stretching the length of the swinger for trails, it will make it too long. If you do want to, max it out at +2.
For a arms, go for a +2+1 setup, that will make the bike 4" wider, and push the stability 1" further forward, it also allows you to keep the stock suspension..They may also lower the front end of the bike a little bit, depending on your setup. If you go with an even wider setup for the front end, youll need to look into a longer travel suspension, as it generally drops the front end too much for the rough stuff. Take the money you were going to spend on the swinger and buy a good set of skid plates for trails, that way you wont bend anything you just bought. Look into a +4 axle as well, theres one presently for sale in the for sale forum
Stay away from Burgard a arms, they are very hard to get ahold of for parts.