I'm not against tolls (eg. I'll gladly drive a road like the NJTP), but I'm very against adding tolls to previously free roads. The only exception I'm okay with (though still not ideal) is replacing large bridges and other similarly large scale projects, eg. the I-5 Columbia Bridge if they ever get around to that. The Abernethy bridge doesn't quite fit that to me, and in this case would just add traffic to surrounding surface streets, particularly OR-43, unless the toll was cheap, like around $1. West Linn, Oregon City, and Gladstone are too connected on a local level for this to make sense, even without factoring in the larger Portland regional traffic.
Also, tolling the highway that bypasses downtown Portland, instead of the one going through downtown, seems pretty backwards. Though I'm sure I-5 will get some form of toll at some point (and it will be more justified than I-205's most likely).