Do you really want to inconvenience POTUS?
A closed, paranoid mind is not going to be swayed by mere loud voices and banners. In fact, there is not much of anything other than money and the voices of the "powerful" and "incorporated" that will attract the attention of POTUS; therefore, if you want to make an impression, you need to inconvenience those people that POTUS does wish to hear - and take money from.
During POTUS's Oregon visit, the means to accomplish inconveniencing POTUS and his contributors and supporters is not to so much to affect our local situation as it is to keep POTUS from making it to his next engagement. Accomplishing this will not occur anywhere near the grounds of the University of Portland. The bottleneck for POTUS is PDX.
Approximately 800 people, strategically located at the following intersections, could effectively delay POTUS for hours. Potentially, 7/8 of those people would not come within 2 miles of POTUS's caravan but the 1/8 that did could be truly debilitating to POTUS's plans for the day.
NE 47th St. north of Columbia Blvd.
NE Alderwoodt north of Columbia Blvd.
NE 82nd Ave. over the top of the Columbia Slough.
NE Alderwood under I-205.
Airport Way, westbound only, ~1/4 west of the I-205 on-ramp.
Marine Drive west of I-205.
Marine Drive west of NE 33rd.
NE 33rd over the Columbia Slough.
Placing 100 people at each of these locations and, borrowing a page from the FlashMob folks ( http://www.flashmob.com/), maintaining communication via cell phones and advance scouts (prior to each location) the safety of the protestors could be increased and the inconvenience to the local population kept to a minimum by placing a road blockage only at the correct location − just prior to POTUS's caravan arriving. The other 7/8 of the protestors could certainly make themselves seen and heard in their respective locations while also remaining vigilant to any potential redirection of the caravan.
Has this idea been posited before? Probably, but it certainly has not been tried and stands to be at least as effective as previous approaches and has the potential to be even more effective since it actually has some impact on POTUS and his supporters rather than being a distracting noise that is soon forgotten.