PLC remote data logging

Hello, I am new to PLCs and looking for some insight. I am tasked with logging data from 4-20ma analog signals and remotely transmitting this data to servers. In addition to this I need a display that shows the data from the inputs in a readable form. The number of inputs needed will vary from 4 to ~70,which is why I think PLCs may be ideal due to their modular and customizable nature. I am wondering if a PLC connected with a modem will work in this situation, or if I should pursue data logging devices that have displays.

You don't mention which PLC you have (or are looking at?) and what is/will be interfaced with it, but most any PLC connected to an HMI or SCADA is capable of displaying and logging data. This data can then be transmitted anywhere you wish over Ethernet.

More information needed!

In many of my application cases, there will be no on-site PC or LAN.
My current plan is to use analog I/O modules from icpdas http://www.icpdas-usa.com/m_7017c.html#specifications. These modules use Modbus RTU. I was hoping then I could set these up in a multidrop rs-485 network, and connect it to a GPRS modem. I planned on using the GTM-201-rs232 http://www.icpdas-usa.com/gtm_201_rs232.html#specifications for this. I would use an rs-485/rs-232 converter (http://www.icpdas-usa.com/i_7520.html) to connect the module network to the modem. I am hoping that the modem can then communicate with a computer at the office acting as the Modbus master.
Is this setup a possible solution, or do I need an on-site PC/PLC to make this work? Can the modem properly act as a communication bridge with a PC back at our offices or does the master need to be on location. Additionally, if this method does work, is there any way one PC could act as master for multiple locations? Thank you for your time and I appreciate any information, I am very new to this.

One important question to ask is how often and how much data do you need to collect.

I don't need to collect much data at all. I only need to gather data a handful of times per day from each input and I only need it sent server side daily.
I have also noted that the modem GD-4500-2G http://www.icpdas-usa.com/gd_4500_sim340.html might be better for my application since it seems to function as a local controller. (As well as hosting 8 inputs for sites that have few sensors.)

I would advise downloading that software package and see if that is something that you want to program. If it was me, I would go the route of a low cost PLC with free software (DoMore, Click or similar) coupled with a simple compatible modem. It may be easier to implement and maintain. Weigh all options and don't just look at hardware costs, development time and service calls are usually much more expensive than hardware.

I would look at Campbell Scientific dataloggers, they are designed for this type of applications.