Create templates and fields using array.

createTemplatesFields.php

<?php

    // .... module

    // create fields and templates using arrays

    public function getTemplatesConfig() {
        // title | field1 | field2 ...
        $templatesArray = array(
            'category'      => array('title'),
            'house'         => array('title','select_category'),
            'price'         => array('title','price','color'),
            'week'          => array('title','select_price','week_date','not_available','booked'),
            'year'          => array('title','year')
            );
        return $templatesArray;
    }

    public function getFieldsConfig() {
        
        // custom php code for a page field
        $select_price_phpcode = <<<_END
\$id = \$_GET['id'];
\$p = \$pages->get(\$id);
return \$p->parents('template=house')->first()->select_category->children();";
_END;
        // fields array, type and label, specific setting as key=>value as they're known to the field
        $fieldsArray = array(
            'booked'            => array('type' => 'Checkbox', 'label' => 'Booked'),
            'color'             => array('type' => 'ColorPicker', 'label' => 'Color'),
            'not_available'     => array('type' => 'Checkbox', 'label' => 'Off'),
            'price'             => array('type' => 'Integer', 'label' => 'Price'),
            'year'              => array('type' => 'Integer', 'label' => 'Year'),
            'week_date'         => array('type' => 'Datetime', 'label' => 'Week Date'),
            'select_category'   => array('type' => 'Page', 'label' => 'Select category',
                                         'settings' => array(
                                                'derefAsPage' => FieldtypePage::derefAsPageOrFalse,
                                                'template_id' => $this->templates->get('category')->id
                                        )),
            'select_price'      => array('type' => 'Page', 'label' => 'Select category',
                                         'settings' => array(
                                                'derefAsPage' => FieldtypePage::derefAsPageOrFalse,
                                                'findPagesCode' => $select_price_phpcode
                                        ))
            );
        return $fieldsArray;
    }

    public function ___install() {

        $tplArray = $this->getTemplatesConfig();

        // add templates without fields so we can reference page fields to template id
        foreach($tplArray as $key => $t) {
            if (!$this->templates->get($key)) {
                $fg = new Fieldgroup();
                $fg->name = $key;
                $fg->save();

                $tp = new Template();
                $tp->name = $key;
                $tp->fieldgroup = $fg;
                $tp->tags = "housemanager";
                $tp->save();
            } else {
                $this->error("Template '$key' already exists!");
            }
        }

        $fieldArray = $this->getFieldsConfig();

        // create fields
        foreach($fieldArray as $key => $field) {
            if (!$this->fields->get($key)) {
                $f = new Field();
                $f->type = $this->modules->get("Fieldtype" . $field['type']);
                $f->tags = "housemanager";
                $f->name = $key;
                $f->label = $field['label'];
                if(isset($field['settings']) && count($field['settings'])) {
                    foreach($field['settings'] as $key => $value) $f->$key = $value;
                }
                $f->save();
            } else {
                $this->error("Field '$key' already exists.");
            }
        }

        // add fields to templates
        foreach($tplArray as $key => $t) {
            $fg = $this->fieldgroups->get($key);
            foreach($t as $f) $fg->add($this->fields->get($f));
            $fg->save();
        }

    }

Thanks Soma! Really helpful when automating these kinds of actions.