Wat Klang Wiang
It's not in any current guidebooks to Chiang Rai, but the temple of Klang Wiang is, I think, worth a look. The temple, particularly the small ubosot (ordination hall), displays a heavy Hindu influence on the typical northern style.
The temple's name means 'center of the city' in the northern dialect, and within the compound is indeed a small pavilion containing a City Pillar. The original City Pillar was in the compound of the temple, but it rotted away and the current version was built in 1992. The 'new' City Pillar is at the top of Doi Tong.
The temple was apparently founded way back in 1432, but it has undergone at least two major rebuildings, along with the many minor tweaks that all Thai temples are constantly undergoing. Most of the main buildings were heavily damaged by a gale in 1903, so all of the buildings you see today were built since then.
In addition to the City Pillar, the compound includes a wiharn, chedi and ubosot as well as school buildings and some other curiosities.
The wiharn faces you as you enter from the street from the east side. The front is intricately decorated with gilded grillwork and red columns. The stairs are lined with nagas, as is typical in northern temples. Although here, the tails of the serpents snake up and around the center columns of the portico.
North of the chapel is a sort of fairy garden with a couple of dioramas extolling the virtues of farm life, etc. Behind the wiharn is a rather elaborate chedi (pagoda) with niches around its three-tiered base. At the very base are some sculpted elephants in full court regalia. The pagoda was built on the place where a revered tree once was, which also got blown down in the storm of 1903. In the compound opposite the chedi, an elaborate two-story building which appears to be a library was completed in the late 2000s.
The very small ubosot next to the pagoda has an extraordinary portico which reminded me of Hindu temples I've seen in Bangkok and Singapore. Like the wiharn, it's all in red and gold.